Year	Number of
1990	59.69
1991	63.13
1992	66.97
1993	71.23
1994	75.83
1995	79.83
1996	82
1997	83.33
1998	85.16
1999	86.56
2000	87.65
2001	87.8
2002	88.08
2003	87.72
2004	88.07
2005	88.61
2006	91.74
2007	94.73
2008	97.93
2009	101.83
2010	106.05
2011	109.17
2012	112.99
2013	116.63
2014	120.73
2015	125.38
2016	130.28