Holdings
[1.]1950,1; 5.1954,1u.3; 6.1955,3u.6; 7.1956,2u.4-6; 8.1957 - 15.1964,2; 16.1965,3u.5; 17.1966,4; 20.1969,5; 26.1975,3-4; 28.1977,5; 29.1978,1-2; 30.1979,1u.5-6; 31.1980,4; 32.1981,2-3; 33.1982,4; 34.1983,2; 35.1984,2; 36.1985,4-5; 37.1986,3-4; 38.1987,3; 39.1988,3; 41.1990,2-4u.6
Holdings gaps
[N=8.1957,1; 9.1958,3; 10.1959,1; 11.1960,6; 13.1962,4]