Year	Number of
1990	76.09
1991	79.72
1992	83.27
1993	88.5
1994	93.1
1995	98.58
1996	103.02
1997	107.13
1998	111.77
1999	115.9
2000	119.62
2001	120.4
2002	120.38
2003	120.95
2004	120.98
2005	122.14
2006	124.22
2007	125.75
2008	127.93
2009	130.33
2010	133.87
2011	138.17
2012	143.56
2013	148.38
2014	153.03
2015	157.93
2016	163.17