Year	Number of
1990	41.38
1991	41.95
1992	42.38
1993	42.74
1994	43.12
1995	43.6
1996	46.71
1997	50.24
1998	54.14
1999	58.34
2000	62.84
2001	67.01
2002	71.25
2003	75.66
2004	80.42
2005	85.77
2006	85.08
2007	84.62
2008	84.4
2009	84.27
2010	84.18
2011	85.71
2012	87.37
2013	89.01
2014	90.66
2015	92.31
2016	94.06