Year	Number of
1990	192.45
1991	195.84
1992	199.89
1993	203.61
1994	208.29
1995	213.15
1996	217.74
1997	222.94
1998	228.12
1999	234.08
2000	240.62
2001	245.68
2002	252.8
2003	262.39
2004	272.01
2005	277.78
2006	279.34
2007	278.58
2008	279.77
2009	282.93
2010	288.96
2011	297.68
2012	308.82
2013	319
2014	328.6
2015	335
2016	346.25