Year | |
---|---|
1997 | 38.1 |
1998 | 24.9 |
1999 | 18.8 |
2000 | 19.8 |
2001 | 19.5 |
2002 | 19.0 |
2003 | 18.1 |
2004 | 16.6 |
2005 | 16.6 |
2006 | 17.4 |
2007 | 18.4 |
2008 | 18.1 |
2009 | 18.4 |
2010 | 18.8 |
2011 | 17.5 |
2012 | 18.6 |
2013 | 19.3 |
2014 | 14.7 |
2015 | 11.1 |
2016 | 10.5 |
2017 | 12.5 |
2018 | 10.9 |
2019 | 11.4 |
2020 | 6.3 |
2021 | 7.2 |
2022 | 6.9 |
2023 | 9.1 |
2024 | 9.6 |