Year	Number of
1990	80.82
1991	84.09
1992	87.18
1993	90.09
1994	93.45
1995	97.51
1996	99.65
1997	101.99
1998	104.59
1999	106.71
2000	108.18
2001	108.48
2002	107.88
2003	107.82
2004	106.83
2005	105.25
2006	104.65
2007	104.14
2008	103.08
2009	102.78
2010	103.33
2011	106.68
2012	110.18
2013	113.74
2014	117.06
2015	120.49
2016	124.28