Year	Number of
1990	85.36
1991	88.39
1992	91.43
1993	94.55
1994	98
1995	101.86
1996	104.31
1997	106.99
1998	109.86
1999	112.98
2000	116.41
2001	122.15
2002	128.39
2003	135.25
2004	142.66
2005	150.7
2006	158.4
2007	166.61
2008	175.47
2009	184.99
2010	195.35
2011	200.78
2012	206.58
2013	212.36
2014	218.34
2015	224.54
2016	231.32