Year	Number of
1990	114.07
1991	121.77
1992	129.64
1993	137.89
1994	146.82
1995	156.8
1996	163.68
1997	171.15
1998	179.11
1999	187.3
2000	195.8
2001	203.26
2002	210.68
2003	218.15
2004	225.88
2005	234.25
2006	242.03
2007	249.96
2008	258.83
2009	268.36
2010	278.86
2011	287.18
2012	296.79
2013	307.27
2014	318.37
2015	330.02
2016	342.97