Year	Number
1961	150.17454247473367
1962	151.1788276702315
1963	152.43236714975845
1964	153.67646667553544
1965	154.81535214982853
1966	156.40596390269422
1967	155.92511358295474
1968	155.5609133086587
1969	155.23598896810117
1970	154.90779699755856
1971	154.59551960174238
1972	156.40165417420522
1973	158.66793775121099
1974	158.55755894590845
1975	160.24170421958215
1976	161.95655503369412
1977	163.63113341443633
1978	165.31533118582647
1979	164.2093162734906
1980	163.14274369664483
1981	162.05973680319386
1982	164.79474226298493
1983	167.4069012640929
1984	169.9936859488076
1985	172.5554642563681
1986	175.1061834098944
1987	178.73139719693688
1988	182.35960745545293
1989	185.99710284886527
1990	181.30393792153166
1991	177.6851457477251
1992	176.90108079290457
1993	175.91109817052458
1994	174.91861425586706
1995	173.92361955728532
1996	173.24703475486496
1997	174.2330092355679
1998	175.30171888333535
1999	176.61551972287953
2000	177.93073149300724
2001	178.89054410471817
2002	180.38901883540564
2003	181.9125167568641
2004	183.46266489774465
2005	185.0388731825525
2006	186.64104065371788