Year	Number of
1990	32.39
1991	30.92
1992	29.2
1993	28.05
1994	27.59
1995	26.84
1996	28.84
1997	30.4
1998	32.75
1999	34.75
2000	37.53
2001	39.35
2002	41.66
2003	42.51
2004	43.97
2005	45.54
2006	48.71
2007	52.35
2008	55.91
2009	59.9
2010	63.92
2011	67.96
2012	70.95
2013	74.32
2014	77.02
2015	80.03
2016	83.25