Year	Number of
1990	58.39
1991	58.39
1992	59.78
1993	61.3
1994	61.41
1995	62.93
1996	63.98
1997	62.36
1998	62.11
1999	61.18
2000	60.19
2001	61.65
2002	58.05
2003	55.75
2004	55.14
2005	56.3
2006	58.23
2007	59.88
2008	61.66
2009	63.45
2010	67.04
2011	69.62
2012	70.97
2013	73.03
2014	77.02
2015	78.54
2016	80.54