| Year | Situation |
| 1956 | Most interesting |
| 1958-1962 | Unprofitable (5 years) |
| 1967 | Rates moved-up |
| 1970 | Boom |
| 1973 | Very good |
| 1975-1977 | Not enough profit for 3 years |
| 1979 | Exciting |
| 1981-1983 | Bad (3 years) |
| 1988 | Good |
| 1989-1991 | Good |
| 1992-1993 | Really Bad (2 years) |
| 1996-1997 | Better |
| 1998 | Good |
| 2000-2008 | Extremely good (8 years) |