Year	Number
1993	18.42383
1994	18.1832
1995	17.45626
1996	17.03285
2002	12.80967
2003	13.10385
2004	12.71507
2005	12.37909
2006	12.27943
2007	11.90202
2008	10.49383
2009	10.41813
2010	10.66796
2011	10.88041
2012	11.21062
2013	12.58244
2014	12.37465
2015	12.3
2016	11.90441
2017	11.87728