Year	Number of
1990	80.11
1991	82.53
1992	84.38
1993	88.71
1994	92.69
1995	96.54
1996	99.56
1997	102.06
1998	103.87
1999	105.02
2000	106
2001	106.77
2002	107.78
2003	107.31
2004	109.95
2005	112.47
2006	117.58
2007	124.49
2008	130.3
2009	137.88
2010	142.96
2011	139.67
2012	137.97
2013	136.62
2014	135.82
2015	136.3
2016	136.38