| Value | Category | 
                                    
                    
                        | -9 | Don't know (SPONTANEOUS) | 
                                    
                    
                        | 0 |  | 
                                    
                    
                        | 50000 |  | 
                                    
                    
                        | 80000 |  | 
                                    
                    
                        | 100000 |  | 
                                    
                    
                        | 145000 |  | 
                                    
                    
                        | 150000 |  | 
                                    
                    
                        | 187000 |  | 
                                    
                    
                        | 200000 |  | 
                                    
                    
                        | 250000 |  | 
                                    
                    
                        | 270000 |  | 
                                    
                    
                        | 300000 |  | 
                                    
                    
                        | 400000 |  | 
                                    
                    
                        | 500000 |  | 
                                    
                    
                        | 540000 |  | 
                                    
                    
                        | 650000 |  | 
                                    
                    
                        | 700000 |  | 
                                    
                    
                        | 750000 |  | 
                                    
                    
                        | 800000 |  | 
                                    
                    
                        | 1000000 |  | 
                                    
                    
                        | 1200000 |  | 
                                    
                    
                        | 1400000 |  | 
                                    
                    
                        | 1500000 |  | 
                                    
                    
                        | 1600000 |  | 
                                    
                    
                        | 1700000 |  | 
                                    
                    
                        | 1800000 |  | 
                                    
                    
                        | 2000000 |  | 
                                    
                    
                        | 2500000 |  | 
                                    
                    
                        | 3000000 |  | 
                                    
                    
                        | 3500000 |  | 
                                    
                    
                        | 3600000 |  | 
                                    
                    
                        | 4000000 |  | 
                                    
                    
                        | 4500000 |  | 
                                    
                    
                        | 5000000 |  | 
                                    
                    
                        | 5500000 |  | 
                                    
                    
                        | 6000000 |  | 
                                    
                    
                        | 6500000 |  | 
                                    
                    
                        | 6800000 |  | 
                                    
                    
                        | 7000000 |  | 
                                    
                    
                        | 7500000 |  | 
                                    
                    
                        | 8000000 |  | 
                                    
                    
                        | 9000000 |  | 
                                    
                    
                        | 10000000 |  | 
                                    
                    
                        | 10500000 |  | 
                                    
                    
                        | 11000000 |  | 
                                    
                    
                        | 11600000 |  | 
                                    
                    
                        | 12000000 |  | 
                                    
                    
                        | 13000000 |  | 
                                    
                    
                        | 14000000 |  | 
                                    
                    
                        | 15000000 |  | 
                                    
                    
                        | 16000000 |  | 
                                    
                    
                        | 17000000 |  | 
                                    
                    
                        | 18000000 |  | 
                                    
                    
                        | 20000000 |  | 
                                    
                    
                        | 25000000 |  | 
                                    
                    
                        | 30000000 |  | 
                                    
                    
                        | 32000000 |  | 
                                    
                    
                        | 35000000 |  | 
                                    
                    
                        | 40000000 |  | 
                                    
                    
                        | 50000000 |  | 
                                    
                    
                        | 60000000 |  | 
                                    
                    
                        | 65000000 |  | 
                                    
                    
                        | 70000000 |  | 
                                    
                    
                        | 80000000 |  | 
                                    
                    
                        | 94000000 |  | 
                                    
                    
                        | 100000000 |  | 
                                    
                    
                        | 108000000 |  | 
                                    
                    
                        | 113000000 |  | 
                                    
                    
                        | 121000000 |  | 
                                    
                    
                        | 150000000 |  | 
                                    
                    
                        | 180000000 |  | 
                                    
                    
                        | 247000000 |  | 
                                    
                    
                        | 312000000 |  | 
                                    
                    
                        | 2000000000 |  | 
                                    
                    
                        | 2500000000 |  | 
                                    
                    
                        | 16000000000 |  | 
                            
            Warning: these figures indicate the number of cases found in the data file. They cannot be interpreted as summary statistics of the population of interest.