Year	Number of
1990	74.65
1991	77.77
1992	81.17
1993	85.07
1994	89.04
1995	93.25
1996	96.74
1997	100.76
1998	105.23
1999	109.56
2000	113.8
2001	117.61
2002	121.36
2003	125.56
2004	129.63
2005	133.53
2006	137.81
2007	143.14
2008	147.85
2009	151.82
2010	155.77
2011	161.43
2012	166.66
2013	170.41
2014	174.33
2015	179.13
2016	186.62