Year	Percent
1960	350.42613
1961	310.89294
1962	294.83272
1963	276.19377
1964	228.51541
1965	228.3539
1966	221.7399
1967	208.47354
1968	205.71576
1969	216.27429
1970	209.17175
1971	203.2862
1972	205.29245
1973	237.68626
1974	271.99991
1975	239.80779
1976	247.47056
1977	282.76007
1978	308.61688
1979	342.95699
1980	364.76516
1981	342.50366
1982	304.46195
1983	281.23888
1984	267.21328
1985	256.53799
1986	258.52358
1987	293.07629
1988	328.25218
1989	310.06219
1990	313.96302
1991	275.01381
1992	260.06964
1993	262.58904
1994	270.3998
1995	276.22593
1996	265.91494
1997	257.00053
1998	246.91732
1999	261.62705
2000	284.18848
2001	266.27965
2002	262.79624
2003	305.27402
2004	325.98363
2005	337.23418
2006	345.41719
2007	312.51189
2008	342.28274
2009	267.98071
2010	280.2864
2011	280.92982
2012	271.13436
2013	257.2687
2014	248.94147
2015	211.57117
2016	203.37757
2017	216.39713