Year	Number of
1990	96.44
1991	95.57
1992	93.46
1993	90.71
1994	87.2
1995	86.11
1996	83.96
1997	85.6
1998	83.44
1999	83.41
2000	83.94
2001	87.99
2002	94.36
2003	99.74
2004	103.91
2005	109.68
2006	114.74
2007	119.17
2008	123.25
2009	126.74
2010	130.36
2011	135.11
2012	139.86
2013	144.48
2014	148.69
2015	153.06
2016	159.14