Year	Number of
1990	43.3
1991	44.61
1992	45.45
1993	46.15
1994	46.89
1995	47.87
1996	48.97
1997	50.34
1998	51.96
1999	53.53
2000	55.12
2001	56.36
2002	57.73
2003	59.22
2004	60.86
2005	62.67
2006	64.4
2007	66.33
2008	68.64
2009	71.02
2010	73.51
2011	76.36
2012	79.5
2013	82.97
2014	86.75
2015	90.64
2016	94.58