Year	Number of
1990	74.72
1991	73.85
1992	73.12
1993	72.99
1994	73.96
1995	76.35
1996	78.6
1997	82.53
1998	87.25
1999	91.69
2000	95.4
2001	95.92
2002	95.55
2003	94.77
2004	94.27
2005	94.52
2006	97.07
2007	100.26
2008	104.04
2009	107.91
2010	111.78
2011	114.17
2012	116.42
2013	118.55
2014	120.84
2015	123.4
2016	126.08