Year	Number of
1990	38.08
1991	39.77
1992	42.1
1993	43.1
1994	44.24
1995	41.92
1996	41.39
1997	37.59
1998	39.82
1999	42.38
2000	43.58
2001	43.97
2002	44.21
2003	43.24
2004	44.24
2005	43.29
2006	41.86
2007	42.29
2008	42.77
2009	42.56
2010	42.03
2011	41.41
2012	42.13
2013	43.09
2014	42.48
2015	42.93
2016	43.11