| 1978 |
| 1980 |
| 1985 |
| 1989 |
| 1990 |
| 1991 |
| 1992 |
| 1993 |
| 1994 |
| 1995 |
| 1996 |
| 1997 |
| 1998 |
| 1999 |
| 2000 |
| 2001 |
| 2002 |
| 2003 |
| 2004 |
| 2005 | |
| 27.45 |
123.72 |
22.2 |
| 31.13 |
179.92 |
17.3 |
| 58.25 |
429.16 |
13.6 |
| 98.21 |
849.44 |
11.6 |
| 101.59 |
904.69 |
11.2 |
| 108.94 |
1089.33 |
10 |
| 118.36 |
1375.7 |
8.6 |
| 166.64 |
1925.91 |
8.7 |
| 209.39 |
2689.28 |
7.8 |
| 248.5 |
3557.55 |
7 |
| 291.75 |
4188.53 |
7 |
| 340.52 |
4686.11 |
7.3 |
| 401.8 |
5052.62 |
8 |
| 477.4 |
5443.92 |
8.8 |
| 658.42 |
6141.03 |
10.7 |
| 917.76 |
6898.34 |
13.3 |
| 1166.58 |
8003.67 |
14.6 |
| 1468.89 |
9705.02 |
15.1 |
| 1805.16 |
11648.7 |
15.5 |
| 2115.36 |
13437.85 |
15.7 | |
