Year	Number of
1990	150.15
1991	146.35
1992	141.89
1993	136.83
1994	132.33
1995	128.74
1996	125.63
1997	123.1
1998	120.9
1999	118.75
2000	116.57
2001	113.79
2002	111.01
2003	109.03
2004	106.97
2005	104.9
2006	107.9
2007	110.86
2008	113.8
2009	117.03
2010	120.74
2011	122.33
2012	124.5
2013	126.08
2014	127.72
2015	129.33
2016	131.84