| Year | |
|---|---|
| 1997 | 132.5 |
| 1998 | 149.4 |
| 1999 | 115.1 |
| 2000 | 111.4 |
| 2001 | 112.0 |
| 2002 | 117.5 |
| 2003 | 117.2 |
| 2004 | 117.3 |
| 2005 | 121.3 |
| 2006 | 123.5 |
| 2007 | 119.4 |
| 2008 | 117.1 |
| 2009 | 119.9 |
| 2010 | 122.0 |
| 2011 | 120.8 |
| 2012 | 124.7 |
| 2013 | 125.9 |
| 2014 | 126.2 |
| 2015 | 129.4 |
| 2016 | 127.2 |
| 2017 | 131.4 |
| 2018 | 134.1 |
| 2019 | 130.4 |
| 2020 | 128.8 |
| 2021 | 126.1 |
| 2022 | 132.9 |
| 2023 | 133.1 |
| 2024 | 135.2 |