Year	Number of
1990	62.17
1991	61.96
1992	61.92
1993	63.7
1994	68.12
1995	70.91
1996	74.07
1997	76.04
1998	75.76
1999	76.85
2000	76.64
2001	75.02
2002	74.38
2003	76.64
2004	78.83
2005	81.65
2006	83.47
2007	85.85
2008	88.28
2009	89.72
2010	91.96
2011	93.3
2012	95.23
2013	97.6
2014	100.12
2015	103.16
2016	106.3