Year	Number of
1990	43.59
1991	44.61
1992	45.18
1993	47.24
1994	48.51
1995	49.63
1996	50.83
1997	51.49
1998	52.79
1999	54.37
2000	55.4
2001	56.43
2002	57.94
2003	59.07
2004	60.33
2005	61.86
2006	63.44
2007	64.71
2008	66.03
2009	67.54
2010	70.28
2011	72.08
2012	73.5
2013	74.82
2014	75.93
2015	77.47
2016	78.9