Year	Number
1998	14.73345
1999	14.39262
2000	14.4605
2001	14.45382
2002	14.6316
2003	14.63564
2004	14.31663
2005	14.44205
2006	14.10397
2007	14.1843
2008	13.81982
2009	13.37923
2010	12.90106
2011	12.97221
2012	12.6979
2013	12.42227
2014	12.35348
2015	12.07721
2016	11.92057
2017	11.45798
2018	11.78596