Year	Number of
1990	168.18
1991	173.34
1992	180.74
1993	187.03
1994	196.34
1995	207.04
1996	215.68
1997	220.9
1998	226.61
1999	225.81
2000	227.28
2001	227.37
2002	228.13
2003	229.57
2004	233.42
2005	237.43
2006	242.11
2007	247.52
2008	254.97
2009	265.7
2010	275.42
2011	284.54
2012	292.57
2013	300.63
2014	308.33
2015	317.17
2016	326.34