Year	Number of
1990	87.99
1991	87.41
1992	89.22
1993	91.61
1994	90.71
1995	92.56
1996	89.87
1997	87.95
1998	86.36
1999	86.18
2000	91.58
2001	94.21
2002	97.66
2003	103.06
2004	106.31
2005	108.76
2006	110.43
2007	113.6
2008	112.62
2009	112.18
2010	113.55
2011	117.69
2012	122.59
2013	129.9
2014	137.31
2015	143.32
2016	149.44