| Value | Category | Cases | |
|---|---|---|---|
| 13 | 1 | 
                                    
                                    0.1%
                                 | |
| 14 | 3 | 
                                    
                                    0.3%
                                 | |
| 15 | 7 | 
                                    
                                    0.7%
                                 | |
| 16 | 26 | 
                                    
                                    2.7%
                                 | |
| 17 | 61 | 
                                    
                                    6.3%
                                 | |
| 18 | 96 | 
                                    
                                    10%
                                 | |
| 19 | 130 | 
                                    
                                    13.5%
                                 | |
| 20 | 163 | 
                                    
                                    17%
                                 | |
| 21 | 142 | 
                                    
                                    14.8%
                                 | |
| 22 | 124 | 
                                    
                                    12.9%
                                 | |
| 23 | 73 | 
                                    
                                    7.6%
                                 | |
| 24 | 51 | 
                                    
                                    5.3%
                                 | |
| 25 | 35 | 
                                    
                                    3.6%
                                 | |
| 26 | 17 | 
                                    
                                    1.8%
                                 | |
| 27 | 8 | 
                                    
                                    0.8%
                                 | |
| 28 | 3 | 
                                    
                                    0.3%
                                 | |
| 88 | Don't know | 20 | 
                                    
                                    2.1%
                                 | 
| 99 | Missing | 1 | 
                                    
                                    0.1%
                                 |