1960, 43.725
1961, 44.051
1962, 44.783
1963, 45.972
1964, 47.592
1965, 49.549
1966, 51.696
1967, 53.847
1968, 55.843
1969, 57.603
1970, 59.085
1971, 60.303
1972, 61.344
1973, 62.281
1974, 63.134
1975, 63.915
1976, 64.631
1977, 65.278
1978, 65.857
1979, 66.377
1980, 66.843
1981, 67.256
1982, 67.618
1983, 67.933
1984, 68.21
1985, 68.451
1986, 68.661
1987, 68.842
1988, 69.002
1989, 69.15
1990, 69.293
1991, 69.437
1992, 69.587
1993, 69.75
1994, 69.935
1995, 70.156
1996, 70.427
1997, 70.747
1998, 71.115
1999, 71.521
2000, 71.955
2001, 72.401
2002, 72.84
2003, 73.257
2004, 73.642
2005, 73.987
2006, 74.291
2007, 74.562
2008, 74.808
2009, 75.032
2010, 75.236
2011, 75.425
2012, 75.602
2013, 75.769
2014, 75.932
2015, 76.092
2016, 76.252