Year	Number of
1990	35.34
1991	34.62
1992	34.77
1993	33.62
1994	34.13
1995	33.06
1996	30.03
1997	30.2
1998	33.51
1999	34.04
2000	36.94
2001	36.97
2002	37.52
2003	37.63
2004	38.41
2005	37.2
2006	37.49
2007	35.65
2008	34.6
2009	34.8
2010	34.55
2011	34.21
2012	34.27
2013	35.64
2014	36.01
2015	36.57
2016	37.07