age cohort  abund
0 1949  59500
1 1949   1970
2 1949    933
3 1949    117
4 1949      7
0 1950  60000
1 1950   2144
2 1950    901
3 1950     95
4 1950      6
0 1951  55500
1 1951   2516
2 1951    865
3 1951    131
4 1951     12
0 1952  51000
1 1952   2694
2 1952   1052
3 1952    199
4 1952     26
0 1953  40000
1 1953   3162
2 1953   1160
3 1953    183
4 1953     17
0 1954  52000
1 1954   2118
2 1954    779
3 1954    159
4 1954     13
0 1955  73000
1 1955   2474
2 1955    911
3 1955    193
4 1955     34
0 1956  67000
1 1956   3352
2 1956   1348
3 1956    302
4 1956     24
0 1957  58500
1 1957   2548
2 1957   1144
3 1957    230
4 1957     12
0 1958  75500
1 1958   2019
2 1958   1088
3 1958    208
4 1958     26
0 1959 100500
1 1959   2528
2 1959    968
3 1959    200
4 1959     19