1970 |
1971 |
1972 |
1973 |
1974 |
|
Spharagemon equale |
0.1 |
0.1 |
0.2 |
0.5 |
1.0 |
Assemblage of 16 species |
3.7 |
5.1 |
8.7 |
15.3 |
48.6 |