Year	Number of
1990	87.76
1991	90.17
1992	91.92
1993	94.2
1994	97.75
1995	101.08
1996	104.63
1997	105.96
1998	108.69
1999	113.05
2000	118.77
2001	123.84
2002	129.13
2003	134.98
2004	141
2005	146.97
2006	153.19
2007	159.68
2008	166.78
2009	174.22
2010	182.06
2011	188.98
2012	196.28
2013	203.8
2014	211.16
2015	218.83
2016	226.31