Year	Number of
1990	60.86
1991	61.64
1992	60.95
1993	58.27
1994	56.16
1995	56.88
1996	55.49
1997	55.67
1998	59.8
1999	66.02
2000	76.95
2001	82.79
2002	90.63
2003	92.04
2004	94.3
2005	97.13
2006	95.61
2007	93.98
2008	91.89
2009	90.67
2010	88.85
2011	85.55
2012	84.29
2013	83.75
2014	82.74
2015	81.34
2016	81.17