Year	Number of
1990	40.88
1991	41.91
1992	41.89
1993	41.55
1994	43.2
1995	45.65
1996	51.23
1997	53.87
1998	59.59
1999	64.36
2000	71.45
2001	75.03
2002	76.9
2003	79.07
2004	80.03
2005	80.63
2006	81.88
2007	82.71
2008	83.81
2009	84.88
2010	85.71
2011	85.3
2012	85.12
2013	85.02
2014	84.48
2015	83.31
2016	83.22