Year	Number of
1990	172.89
1991	176.93
1992	176.7
1993	177.27
1994	182.24
1995	185.42
1996	190.07
1997	186.2
1998	186.47
1999	190.39
2000	198.08
2001	206.12
2002	213.9
2003	222.37
2004	230.15
2005	237.35
2006	245.53
2007	253.59
2008	263.2
2009	273.81
2010	284.48
2011	296.49
2012	307.72
2013	318.37
2014	328.85
2015	338.25
2016	348.81