Year	Number of
1990	46.41
1991	48.19
1992	50.24
1993	52.21
1994	54.37
1995	57.04
1996	59.72
1997	60.59
1998	59.9
1999	62.16
2000	66.7
2001	67.95
2002	72.89
2003	77.52
2004	80.53
2005	82.26
2006	81.9
2007	81.02
2008	85.27
2009	86.01
2010	86.81
2011	91.76
2012	94.39
2013	102.35
2014	105.7
2015	109.27
2016	112.62