Year	Number of
1990	167.62
1991	170.4
1992	173.42
1993	172.36
1994	179.43
1995	176.42
1996	176.99
1997	177.57
1998	180.99
1999	193.37
2000	200.56
2001	211.59
2002	220.08
2003	229.27
2004	243.67
2005	256.7
2006	268.3
2007	278.66
2008	291.16
2009	302.15
2010	312.62
2011	322.48
2012	332.67
2013	343.82
2014	353.88
2015	365.39
2016	377.59