| Age |
Drivers1 |
| 1998 |
2004 |
| Under 16 |
15.4 |
14 |
| 16-20 |
22.2 |
22.8 |
| 21-24 |
37.4 |
39.1 |
| 25-29 |
33.4 |
34.2 |
| 30-34 |
30.9 |
28.7 |
| 35-39 |
29.9 |
27.1 |
| 40-44 |
25.6 |
26.1 |
| 45-49 |
22.8 |
23.5 |
| 50-54 |
18.1 |
19.2 |
| 55-59 |
15.3 |
16.5 |
| 60-64 |
11.2 |
13.3 |
| 65-69 |
10 |
11.3 |
| 70-74 |
8.5 |
8.5 |
| 75-79 |
6.8 |
7.5 |
| 80+ |
5.4 |
6 |
1 Drivers whose age is unknown are excluded.