Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
|  | Average population (x 1000) | Live births | Deaths | Natural change | Crude birth rate (per 1000) | Crude death rate (per 1000) | Natural change (per 1000) |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 1970 | 38 | 761 | 299 | 462 | 20.0 | 7.9 | 12.2 |
| 1975 | 42 | 857 | 317 | 540 | 20.4 | 7.5 | 12.9 |
| 1980 | 46 | 996 | 333 | 663 | 21.7 | 7.2 | 14.4 |
| 1985 | 51 | 1 104 | 370 | 734 | 21.6 | 7.3 | 14.4 |
| 1990 | 51 | 842 | 360 | 482 | 16.4 | 7.0 | 9.4 |
| 1991 | 50 | 789 | 335 | 454 | 15.8 | 6.7 | 9.1 |
| 1992 | 48 | 692 | 401 | 291 | 14.4 | 8.3 | 6.0 |
| 1993 | 46 | 617 | 448 | 169 | 13.4 | 9.7 | 3.7 |
| 1994 | 44 | 585 | 518 | 67 | 13.3 | 11.8 | 1.5 |
| 1995 | 43 | 537 | 501 | 36 | 12.6 | 11.8 | 0.8 |
| 1996 | 42 | 486 | 441 | 45 | 11.7 | 10.6 | 1.1 |
| 1997 | 41 | 483 | 374 | 109 | 11.9 | 9.2 | 2.7 |
| 1998 | 40 | 498 | 368 | 130 | 12.6 | 9.3 | 3.3 |
| 1999 | 39 | 448 | 376 | 72 | 11.6 | 9.7 | 1.9 |
| 2000 | 38 | 460 | 438 | 22 | 12.0 | 11.4 | 0.6 |
| 2001 | 39 | 562 | 438 | 124 | 14.5 | 11.3 | 3.2 |
| 2002 | 39 | 608 | 397 | 211 | 15.5 | 10.1 | 5.4 |
| 2003 | 39 | 625 | 386 | 239 | 15.9 | 9.8 | 6.1 |
| 2004 | 39 | 637 | 345 | 292 | 16.5 | 8.9 | 7.6 |
| 2005 | 38 | 548 | 369 | 179 | 14.5 | 9.7 | 4.7 |
| 2006 | 37 | 540 | 347 | 193 | 14.5 | 9.3 | 5.2 |
Question:
which years have an average population of no less than 50,000?
Answer:
1985, 1990, 1991