Year	Number of
1990	244.88
1991	252.2
1992	261.14
1993	270.5
1994	280.04
1995	294.32
1996	310.11
1997	319.15
1998	320.7
1999	312.49
2000	295.73
2001	281.42
2002	271.3
2003	265.39
2004	260.29
2005	255.6
2006	249.73
2007	242.46
2008	239
2009	243.02
2010	249.18
2011	249.49
2012	248.56
2013	248.85
2014	247.07
2015	252.45
2016	259.18