| Year | Value | | 2019 | 34,065.556846186 | | 2018 | 33,728.968657989 | | 2017 | 4,486 | | 2016 | 4,486 | | 2014 | 251,652 | | 2013 | 258,336 | | 2012 | 178,709.7 | | 2011 | 177,005.4 | | 2010 | 163,812.74580862 | | 1991 | 46,100 | | 1990 | 87,600 | | 1989 | 89,200 | | 1988 | 104,700 | | 1987 | 128,400 | | 1986 | 122,000 | | 1985 | 99,800 | | 1984 | 130,000 | | 1983 | 117,200 | | 1982 | 99,300 | | 1981 | 115,800 | | 1980 | 90,000 | | 1979 | 36,500 | | 1978 | 36,000 | | 1977 | 34,000 | | 1976 | 38,000 | | 1975 | 35,000 | | 1974 | 35,000 | | 1973 | 33,000 | | 1972 | 31,400 | | 1971 | 29,800 | | 1970 | 25,700 |
|