| 2,42 | 2,62 | 3,50 | 3,96 | - |
| 1926–1930 | 2,01 | 2,30 | 2,10 | 3,30 | 3,75 | 6,04 |
| 1931–1935 | 1,79 | 2,16 | 1,84 | 3,07 | 3,50 | 4,53 |
| 1936–1940 | 1,98 | 2,07 | 2,24 | 3,00 | 2,77 | 4,66 |
| 1941–1945 | 2,39 | 2,11 | 1,90 | 2,56 | 2,72 | - |
| 1946–1950 | 2,19 | 2,98 | 2,07 | 2,77 | 2,68 | 3,13 |
| 1950–1955 | 2,18 | 2,73 | 2,16 | 2,32 | 2,52 | 2,51 |
| 1955–1960 | 2,49 | 2,71 | 2,30 | 2,35 | 2,75 | 2,62 |
| 1961–1965 | 2,81 | 2,85 | 2,49 | 2,55 | 2,89 | 2,48 |
| 1965–1970 | 2,52 | 2,61 | 2,32 | 2,49 | 2,93 | 2,02 |
| 1971–1975 | 2,04 | 2,31 | 1,64 | 2,28 | 2,89 | 1,98 |
| 1975–1980 | 1,72 |
