Year	Number of
1990	206.58
1991	212.55
1992	215.8
1993	215.61
1994	218.09
1995	224.49
1996	230.08
1997	239.95
1998	251.86
1999	261.38
2000	270.84
2001	275.49
2002	285.81
2003	295.03
2004	300.62
2005	304.85
2006	305.89
2007	304.95
2008	308.34
2009	310.89
2010	310.69
2011	308.06
2012	307.9
2013	310.19
2014	314.1
2015	318.97
2016	322.87