Year	Number of
1990	79.46
1991	81.38
1992	82.79
1993	85.74
1994	89.21
1995	94.78
1996	97.59
1997	101.73
1998	104.18
1999	106.6
2000	105.81
2001	104.01
2002	102.17
2003	99.23
2004	93.4
2005	84.72
2006	80.05
2007	76.4
2008	75.09
2009	75.06
2010	78.33
2011	80.15
2012	82.5
2013	85.33
2014	88.25
2015	91.16
2016	93.79