Year	Number of
1990	61.63
1991	64.67
1992	68.3
1993	72.28
1994	76.22
1995	79.94
1996	82.25
1997	84.09
1998	85.5
1999	86.91
2000	88.48
2001	89.23
2002	90.06
2003	91
2004	92.15
2005	93.58
2006	95.76
2007	98.26
2008	101.2
2009	104.4
2010	107.84
2011	110.54
2012	113.43
2013	116.39
2014	119.59
2015	123.07
2016	126.91