Year	Number of
1990	88.7
1991	101.18
1992	111.89
1993	125.55
1994	140.07
1995	157.34
1996	173.84
1997	189.13
1998	206.61
1999	223.21
2000	244.82
2001	262.34
2002	280.71
2003	302.91
2004	313.04
2005	323.61
2006	331.51
2007	335.12
2008	338.37
2009	341.07
2010	348.36
2011	352.44
2012	348.79
2013	349.75
2014	351.65
2015	352.91
2016	357.87