Year	Number of
1990	42.37
1991	42.47
1992	44.69
1993	47.18
1994	50.18
1995	51.13
1996	49.45
1997	50.38
1998	52.14
1999	49.66
2000	48.88
2001	51.72
2002	52.19
2003	54.38
2004	53.12
2005	55.72
2006	59.05
2007	59.71
2008	58.55
2009	59.93
2010	59.38
2011	58.77
2012	57.4
2013	59.32
2014	58.75
2015	58.72
2016	59.07