Year	Number of
1990	69.79
1991	71.13
1992	72.78
1993	74.59
1994	76.47
1995	78.37
1996	77.2
1997	76
1998	74.77
1999	73.51
2000	72.21
2001	74.01
2002	75.62
2003	77.38
2004	79.19
2005	81.16
2006	85.53
2007	90.43
2008	95.92
2009	101.9
2010	108.36
2011	113.86
2012	119.66
2013	125.53
2014	131.73
2015	138.34
2016	145.52