| Year | |
|---|---|
| 1997 | 124.0 |
| 1998 | 98.4 |
| 1999 | 83.2 |
| 2000 | 90.5 |
| 2001 | 100.7 |
| 2002 | 110.5 |
| 2003 | 114.6 |
| 2004 | 118.1 |
| 2005 | 121.9 |
| 2006 | 113.3 |
| 2007 | 108.7 |
| 2008 | 112.7 |
| 2009 | 120.8 |
| 2010 | 123.2 |
| 2011 | 123.6 |
| 2012 | 124.4 |
| 2013 | 127.5 |
| 2014 | 119.5 |
| 2015 | 121.4 |
| 2016 | 127.7 |
| 2017 | 132.5 |
| 2018 | 136.3 |
| 2019 | 136.1 |
| 2020 | 122.2 |
| 2021 | 110.3 |
| 2022 | 112.9 |
| 2023 | 112.8 |
| 2024 | 113.4 |