Official exchange rate refers to the exchange rate determined by national authorities or to the rate determined in the legally sanctioned exchange market. It is calculated as an annual average based on monthly averages (local currency units relative to the U.S. dollar).
| Date | Valeur | Modifier , % |
|---|---|---|
| 1998 | 149,4 | 2,04 % |
| 1997 | 146,4 | 15,59 % |
| 1996 | 126,7 | 1,58 % |
| 1995 | 124,7 | -6,92 % |
| 1994 | 134,0 | 5,26 % |
| 1993 | 127,3 | 24,30 % |
| 1992 | 102,4 | -1,47 % |
| 1991 | 103,9 | 1,94 % |
| 1990 | 101,9 | -13,89 % |
| 1989 | 118,4 | 1,62 % |
| 1988 | 116,5 | -5,66 % |
| 1987 | 123,5 |