Year	Number
1993	16.7045
1994	16.81102
1995	16.08921
1996	16.07632
1997	16.60853
1998	15.50295
1999	15.94615
2000	16.04047
2001	16.04122
2002	15.99484
2003	15.89761
2004	16.21055
2005	16.05287
2006	16.09276
2007	15.69711
2008	15.52709
2009	15.72033
2010	14.95304
2011	15.01985
2012	14.8059
2013	14.33652
2014	14.35103
2015	14.69959
2016	14.46607
2017	14.01868