Year	Number of
1990	211.15
1991	215.25
1992	223.16
1993	235.53
1994	242.15
1995	249.7
1996	258.92
1997	269.64
1998	277.58
1999	286.43
2000	299.41
2001	302.63
2002	317.84
2003	327.27
2004	341.37
2005	359.92
2006	377.46
2007	395.61
2008	410.65
2009	427.66
2010	447.46
2011	464.61
2012	482.07
2013	502.05
2014	521.26
2015	542.76
2016	567.22