| January/December | ( . . . . U.S.$/ton . . . . ) | ( . . . 1982-84=100 . . . ) | ( . U.S.$/ton . .) | (1984-87=100) | ||||||
| 1992 | 278 | 180 | 340 | 110 | 112 | 103 | 430 | 394 | 89 | 85 |
| 1993 | 250 | 161 | 326 | 100 | 102 | 92 | 479 | 378 | 93 | 100 |
| 1994 | 289 | 186 | 379 | 114 | 118 | 104 | 616 | 530 | 120 | 129 |
| 1995 | 336 | 268 | 361 | 129 | 124 | 146 | 625 | 626 | 129 | 136 |
| 1995 - August | 354 | 293 | 343 | 135 | 128 | 157 | 591 | 610 | 122 | 127 |
| 1996 - March | 369 | 260 | 395 | 141 | 138 | 152 | 538 | 522 | 112 | 123 |
| April | 345 | 247 | 401 | 135 | 132 | 144 | 547 | 517 | 114 | 127 |
| May | 353 | 246 | 408 | 135 | 134 | 139 | 538 | 522 | 112 | 123 |
| June | 363 | 237 | 419 | 137 | 137 | 139 | 583 | 562 | 121 | 133 |
| July | 371 | 229 | 447 | 139 | 140 | 135 | 608 | 575 | 126 | 140 |
| August I | 355 | 223 | 446 | ) | 610 | 565 | 125 | 138 | ||
| II | 348 | 223 | 446 | ) 135 | 137 | 129 | 588 | 550 | 123 | 135 |
| III | 344 | 210 | 446 | ) | 588 | 550 | 123 | 135 | ||
| IV | 344 | 215 | 446 | ) | 575 | 533 | 122 | 134 | ||