Year	Number of
1990	30.24
1991	30.13
1992	30.71
1993	31.3
1994	32.23
1995	32.14
1996	31.56
1997	31.22
1998	34.58
1999	36.14
2000	42.43
2001	41.55
2002	42.69
2003	46.38
2004	45.97
2005	46.31
2006	45.14
2007	45.53
2008	48.13
2009	47.66
2010	48.87
2011	46.95
2012	46.73
2013	46.87
2014	45.7
2015	44.48
2016	43.04