Year	Number of
1990	45.35
1991	47.69
1992	50.15
1993	52.63
1994	55.15
1995	57.98
1996	57.25
1997	56.64
1998	56.1
1999	55.51
2000	54.88
2001	58.7
2002	63.14
2003	67.91
2004	72.75
2005	77.65
2006	80.36
2007	83.19
2008	86.07
2009	88.98
2010	91.94
2011	93.91
2012	96.09
2013	98.2
2014	100.73
2015	103.35
2016	106.12