Year	Number of
1990	45.68
1991	47.33
1992	49.26
1993	51.22
1994	53.37
1995	55.98
1996	58.73
1997	59.14
1998	58.07
1999	60.21
2000	64.72
2001	65.67
2002	70.21
2003	74.51
2004	77.21
2005	78.78
2006	78.32
2007	77.43
2008	81.49
2009	82.21
2010	83.01
2011	87.97
2012	90.78
2013	98.72
2014	102.39
2015	106.82
2016	110.95