Year	Number of
1990	106.79
1991	108.17
1992	109.4
1993	110.89
1994	112.36
1995	114.63
1996	110.66
1997	106.26
1998	102.63
1999	97.84
2000	95.74
2001	90.3
2002	87.87
2003	86.62
2004	86.67
2005	87.34
2006	88.15
2007	89.73
2008	91.18
2009	93.15
2010	96.55
2011	100.63
2012	105.21
2013	110
2014	115.26
2015	121.19
2016	127.43