Year	Number of
1990	39.66
1991	40.02
1992	40.4
1993	40.74
1994	41.12
1995	41.63
1996	43.68
1997	45.88
1998	48.2
1999	50.54
2000	53.12
2001	56.29
2002	59.82
2003	63.63
2004	67.83
2005	72.33
2006	75.08
2007	78.14
2008	81.59
2009	85.27
2010	89.2
2011	91.94
2012	94.77
2013	97.64
2014	100.73
2015	103.83
2016	107.1