Year	Number of
1990	43.72
1991	43.72
1992	41.92
1993	40.47
1994	40.34
1995	40.48
1996	41.36
1997	42.53
1998	43.98
1999	45.83
2000	48.1
2001	50.78
2002	53.89
2003	56.9
2004	59.86
2005	62.77
2006	65.17
2007	67.48
2008	69.65
2009	71.58
2010	74.06
2011	76.7
2012	79.89
2013	83.12
2014	86.65
2015	90.77
2016	95.38