Year	Number of
1990	46.28
1991	48.02
1992	50.07
1993	52.45
1994	55.1
1995	57.46
1996	60.26
1997	62.96
1998	66.21
1999	66.54
2000	68.52
2001	70.94
2002	72.8
2003	78.32
2004	79.62
2005	82.87
2006	85.74
2007	89.48
2008	95.26
2009	97.65
2010	101.46
2011	104.72
2012	108.48
2013	112.93
2014	117.68
2015	122.39
2016	127.5