| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 11 | 
                                    
                                    1.2%
                                 | 
| -7 | 5 | 
                                    
                                    0.5%
                                 | |
| 1 | One year or less | 16 | 
                                    
                                    1.7%
                                 | 
| 2 | 8 | 
                                    
                                    0.8%
                                 | |
| 3 | 12 | 
                                    
                                    1.3%
                                 | |
| 4 | 13 | 
                                    
                                    1.4%
                                 | |
| 5 | 32 | 
                                    
                                    3.4%
                                 | |
| 6 | 15 | 
                                    
                                    1.6%
                                 | |
| 7 | 12 | 
                                    
                                    1.3%
                                 | |
| 8 | 20 | 
                                    
                                    2.1%
                                 | |
| 9 | 6 | 
                                    
                                    0.6%
                                 | |
| 10 | 62 | 
                                    
                                    6.5%
                                 | |
| 11 | 8 | 
                                    
                                    0.8%
                                 | |
| 12 | 15 | 
                                    
                                    1.6%
                                 | |
| 13 | 8 | 
                                    
                                    0.8%
                                 | |
| 14 | 12 | 
                                    
                                    1.3%
                                 | |
| 15 | 80 | 
                                    
                                    8.4%
                                 | |
| 16 | 19 | 
                                    
                                    2%
                                 | |
| 17 | 16 | 
                                    
                                    1.7%
                                 | |
| 18 | 32 | 
                                    
                                    3.4%
                                 | |
| 19 | 15 | 
                                    
                                    1.6%
                                 | |
| 20 | 140 | 
                                    
                                    14.7%
                                 | |
| 21 | 12 | 
                                    
                                    1.3%
                                 | |
| 22 | 25 | 
                                    
                                    2.6%
                                 | |
| 23 | 13 | 
                                    
                                    1.4%
                                 | |
| 24 | 8 | 
                                    
                                    0.8%
                                 | |
| 25 | 67 | 
                                    
                                    7%
                                 | |
| 26 | 11 | 
                                    
                                    1.2%
                                 | |
| 27 | 21 | 
                                    
                                    2.2%
                                 | |
| 28 | 15 | 
                                    
                                    1.6%
                                 | |
| 29 | 9 | 
                                    
                                    0.9%
                                 | |
| 30 | 98 | 
                                    
                                    10.3%
                                 | |
| 31 | 3 | 
                                    
                                    0.3%
                                 | |
| 32 | 3 | 
                                    
                                    0.3%
                                 | |
| 33 | 9 | 
                                    
                                    0.9%
                                 | |
| 34 | 4 | 
                                    
                                    0.4%
                                 | |
| 35 | 37 | 
                                    
                                    3.9%
                                 | |
| 36 | 4 | 
                                    
                                    0.4%
                                 | |
| 37 | 6 | 
                                    
                                    0.6%
                                 | |
| 38 | 7 | 
                                    
                                    0.7%
                                 | |
| 39 | 5 | 
                                    
                                    0.5%
                                 | |
| 40 | 32 | 
                                    
                                    3.4%
                                 | |
| 42 | 1 | 
                                    
                                    0.1%
                                 | |
| 43 | 2 | 
                                    
                                    0.2%
                                 | |
| 45 | 1 | 
                                    
                                    0.1%
                                 | |
| 48 | 1 | 
                                    
                                    0.1%
                                 | |
| 50 | 1 | 
                                    
                                    0.1%
                                 | |
| 52 | 1 | 
                                    
                                    0.1%
                                 | |
| 60 | 2 | 
                                    
                                    0.2%
                                 |