| 1996 | 16.521 | 16.556 | 16.115 | 17.515 |
| 1997 | 17.444 | 17.683 | 17.427 | 19.108 |
| 1998 | 18.818 | 18.934 | 18.146 | 18.862 |
| 1999 | 18.342 | 18.255 | 18.000 | 19.855 |
| 2000 | 19.490 | 19.374 | 18.982 | 20.572 |
| 2001 | 20.202 | 20.216 | 19.542 | 21.050 |
| 2002 | 20.506 | 20.733 | 20.328 | 21.957 |
| 2003 | 21.449 | 21.616 | 21.141 | 22.737 |
| 2004 | 22.508 | 22.974 | 22.874 | 24.854 |
| 2005 | 23.933 | 24.330 | 24.062 | 26.238 |
| 2006 | 25.397 | 25.963 | 25.509 | 27.921 |
| 2007 | 26.844 | 27.397 | 26.615 | 29.075 |
| 2008 | 28.286 | 28.663 | 27.527 | 29.334 |
| 2009 | 27.495 | 27.662 | 27.251 | 29.622 |
| 2010 | 28.005 | 29.422 | 29.300 | 31.851 |
| 2011 | 30.581 | 31.314 | 30.540 | 33.390 |
| 2012 | 32.147 | 33.040 | 32.252 | 35.077 |
| 2013 | 33.318 | 34.407 | 33.682 | 36.469 |
| 2014 | 34.260 | 34.916 | 34.023 | 37.113 |
| 2015 | 35.037 | 35.759 | 34.798 | 37.951 |
| 2016 | 36.073 | 36.216 | 35.430 | 38.224 |
| 2017 | 35.930 | 36.360 | 36.144 | 39.375 |
| 2018 | 37.628 | 38.270 | 37.076 | 40.785 |
|