Year	Number of
1990	78.92
1991	84.01
1992	89.34
1993	94.98
1994	100.37
1995	104.72
1996	108.09
1997	110.33
1998	111.71
1999	113.07
2000	116.35
2001	118.84
2002	119.53
2003	123.23
2004	125.73
2005	127.1
2006	128.37
2007	130.53
2008	133.11
2009	138.59
2010	143.05
2011	146.85
2012	149.49
2013	152.8
2014	156.59
2015	159.36
2016	161.28