Year	Number of
1990	84.97
1991	90
1992	94.22
1993	98.27
1994	101.49
1995	104.79
1996	108.46
1997	114.37
1998	118.5
1999	120.94
2000	124.3
2001	127.72
2002	130.9
2003	133.71
2004	134.38
2005	135.17
2006	135.14
2007	133.93
2008	134.51
2009	135.62
2010	136.54
2011	137.27
2012	139.38
2013	142.48
2014	145.15
2015	149.13
2016	153.32