Year	Number of
1990	77.55
1991	82.3
1992	87.3
1993	92.74
1994	99.56
1995	104.11
1996	106.04
1997	107.59
1998	110.51
1999	112.34
2000	112.87
2001	114.81
2002	116.77
2003	115.99
2004	116.67
2005	117.37
2006	121.38
2007	124.51
2008	127.49
2009	131.74
2010	135.92
2011	139.74
2012	143.77
2013	148
2014	152.1
2015	156.95
2016	162.25