Year	Number of
1990	144.76
1991	150.03
1992	156
1993	162.69
1994	169.45
1995	176.48
1996	181.48
1997	187.25
1998	191.71
1999	196.8
2000	202.96
2001	208.74
2002	215.16
2003	222.61
2004	230.62
2005	240.17
2006	250.2
2007	260.53
2008	272.16
2009	284.62
2010	298.92
2011	309.27
2012	321.51
2013	335.16
2014	349.5
2015	362.9
2016	376.26