Year	Number of
1990	141.13
1991	144.32
1992	148.36
1993	152.81
1994	157.58
1995	162.71
1996	167.21
1997	172.05
1998	177.3
1999	182.89
2000	189.06
2001	194.16
2002	199.93
2003	206.37
2004	213.1
2005	220.27
2006	227.14
2007	234.02
2008	241.67
2009	249.88
2010	258.97
2011	267.16
2012	276.18
2013	285.82
2014	296.21
2015	307.35
2016	318.81