Year | |
---|---|
2001 | 15.1 |
2002 | 15.7 |
2003 | 16.9 |
2004 | 18.6 |
2005 | 19.8 |
2006 | 17.9 |
2007 | 19.9 |
2008 | 19.2 |
2009 | 17.0 |
2010 | 18.3 |
2011 | 16.2 |
2012 | 16.8 |
2013 | 17.1 |
2014 | 17.7 |
2015 | 18.6 |
2016 | 16.0 |
2017 | 16.8 |
2018 | 14.0 |
2019 | 14.7 |
2020 | 14.3 |
2021 | 13.1 |