Year	Number of
1990	45.99
1991	44.26
1992	44.91
1993	44.77
1994	45.27
1995	47.69
1996	46.22
1997	43.99
1998	42.41
1999	40.04
2000	40.29
2001	39.56
2002	37.35
2003	37.06
2004	36.63
2005	36.5
2006	35.98
2007	35.96
2008	36.86
2009	37.14
2010	36.19
2011	36.29
2012	36.39
2013	36.7
2014	36.8
2015	36.79
2016	36.93