Year	Number of
1990	35.72
1991	37.77
1992	39.77
1993	41.74
1994	44.15
1995	47.17
1996	50.12
1997	53.7
1998	56.74
1999	60.35
2000	63.72
2001	66.41
2002	69.53
2003	73.21
2004	79.61
2005	91.27
2006	103
2007	124.76
2008	144.25
2009	168.99
2010	195.8
2011	218.03
2012	234.01
2013	246.76
2014	260.27
2015	276.48
2016	296.3