Year	Number of
1990	41.43
1991	41.25
1992	42.68
1993	43.43
1994	44.73
1995	47.59
1996	47.21
1997	46.18
1998	45.69
1999	44.73
2000	45.95
2001	46.26
2002	45.33
2003	46.07
2004	46.65
2005	47.64
2006	48.15
2007	49.25
2008	51.23
2009	52.57
2010	52.56
2011	53.89
2012	55.27
2013	56.87
2014	58.34
2015	59.75
2016	61.19