Year	Number of
1990	153.48
1991	157.96
1992	163.95
1993	170.38
1994	176.04
1995	180.29
1996	178.59
1997	174.42
1998	177.08
1999	175.94
2000	173.02
2001	176.41
2002	180.9
2003	186.59
2004	189.01
2005	193.29
2006	197.18
2007	202.58
2008	208.77
2009	208.7
2010	210.57
2011	216.14
2012	219.54
2013	221.13
2014	226.36
2015	231.62
2016	236.95