| Year | |
|---|---|
| 1997 | 373.8 |
| 1998 | 408.1 |
| 1999 | 296.1 |
| 2000 | 319.0 |
| 2001 | 317.2 |
| 2002 | 347.4 |
| 2003 | 352.2 |
| 2004 | 371.4 |
| 2005 | 383.2 |
| 2006 | 391.1 |
| 2007 | 387.1 |
| 2008 | 388.0 |
| 2009 | 398.7 |
| 2010 | 388.3 |
| 2011 | 382.9 |
| 2012 | 388.4 |
| 2013 | 383.4 |
| 2014 | 386.2 |
| 2015 | 395.5 |
| 2016 | 405.4 |
| 2017 | 418.7 |
| 2018 | 431.8 |
| 2019 | 433.3 |
| 2020 | 441.7 |
| 2021 | 455.5 |
| 2022 | 461.3 |
| 2023 | 461.9 |
| 2024 | 466.7 |