1972  533.00  545.80  549.20  556.00  556.60
      1973  536.60  537.20  538.40  540.60  543.00
      1974  532.80  535.20  535.60  539.00  541.40
      1975  526.60  531.00  531.80  534.20  535.00
      1976  507.12  521.80  525.40  528.40  534.90
      1977  516.80  526.30  526.40  526.60  529.20
      1978  512.10  513.20  513.50  520.90  522.30
      1979  511.80  516.40  521.30  521.60  524.10
      1980  513.53  513.90  514.00  516.00  520.40
      1981  514.30  514.80  518.35  524.64  524.65
      1982  506.78  509.36  509.71  511.67  513.40
      1983  512.08  514.02  514.60  514.62  515.06
      1984  502.62  509.59  512.00  513.57  514.91
      1985  505.83  507.83  508.83  515.74  516.51
      1986  513.99  514.10  514.43  515.92  516.00
      1987  518.10  518.50  518.73  519.28  519.45
      1988  506.53  507.15  509.02  510.45  511.67
      1989  518.48  518.51  518.97  520.85  522.12
      1990  518.38  519.46  523.14  523.68  524.07
      1991  512.00  515.72  515.82  516.05  516.06
      1992  513.72  516.63  517.92  518.45  519.94