Year	Number of
1990	48.49
1991	49.82
1992	51.44
1993	53.54
1994	56.04
1995	59.71
1996	61.83
1997	66.15
1998	69.88
1999	75.36
2000	80.96
2001	83.38
2002	85.47
2003	89.66
2004	91.31
2005	92.09
2006	93.64
2007	94.47
2008	95.74
2009	99.93
2010	97.64
2011	97.61
2012	99.9
2013	102.29
2014	105.46
2015	108.64
2016	110.78