Year	Number of
1990	148.89
1991	149.22
1992	148.39
1993	149.19
1994	144.62
1995	140.09
1996	138.61
1997	134.92
1998	132.6
1999	131.95
2000	130.09
2001	126.75
2002	129.85
2003	128.9
2004	128.66
2005	129.04
2006	128.75
2007	127.38
2008	124.32
2009	122.24
2010	120.92
2011	120.93
2012	119.98
2013	119.71
2014	120.73
2015	124.59
2016	126.41