Year	Number of
1990	130.12
1991	132.41
1992	131.17
1993	129.39
1994	125.76
1995	122.73
1996	123.55
1997	127.72
1998	135.77
1999	142.88
2000	148.72
2001	153.12
2002	169.77
2003	192.48
2004	215.04
2005	222.25
2006	231.98
2007	237.64
2008	245.07
2009	259.06
2010	264.18
2011	278.76
2012	300.64
2013	293.66
2014	301.06
2015	282.54
2016	276.52