| Year | |
|---|---|
| 1997 | 106.4 |
| 1998 | 115.1 |
| 1999 | 78.9 |
| 2000 | 82.1 |
| 2001 | 84.5 |
| 2002 | 93.9 |
| 2003 | 101.6 |
| 2004 | 105.2 |
| 2005 | 113.1 |
| 2006 | 116.6 |
| 2007 | 118.1 |
| 2008 | 116.6 |
| 2009 | 129.6 |
| 2010 | 130.9 |
| 2011 | 127.4 |
| 2012 | 125.9 |
| 2013 | 117.2 |
| 2014 | 122.7 |
| 2015 | 107.5 |
| 2016 | 104.2 |
| 2017 | 94.4 |
| 2018 | 91.7 |
| 2019 | 109.7 |
| 2020 | 105.7 |
| 2021 | 105.8 |
| 2022 | 87.5 |
| 2023 | 92.1 |
| 2024 | 92.3 |