Year	Number of
1990	135.84
1991	142.45
1992	150.39
1993	165.26
1994	181.54
1995	204.73
1996	214.2
1997	223.34
1998	230.42
1999	232.89
2000	239.34
2001	250.26
2002	260.85
2003	272
2004	291.4
2005	304.94
2006	311.97
2007	325.46
2008	336.54
2009	352.41
2010	365.62
2011	379.64
2012	390.85
2013	398.29
2014	415.48
2015	426.75
2016	439.98