| Año | Valor |
|---|---|
| 1980-01-01 | 18.879372 |
| 1981-01-01 | 16.363473 |
| 1982-01-01 | 15.284648 |
| 1983-01-01 | 17.515943 |
| 1984-01-01 | 17.506599 |
| 1985-01-01 | 15.671381 |
| 1986-01-01 | 9.175591 |
| 1987-01-01 | 9.146337 |
| 1988-01-01 | 9.609420 |
| 1989-01-01 | 10.929304 |
| 1990-01-01 | 11.382628 |
| 1991-01-01 | 10.091494 |
| 1992-01-01 | 7.685001 |
| 1993-01-01 | 7.258180 |
| 1994-01-01 | 8.836968 |
| 1995-01-01 | 10.608859 |
| 1996-01-01 | 11.544671 |
| 1997-01-01 | 11.383512 |
| 1998-01-01 | 10.722719 |
| 1999-01-01 | 8.365394 |
Fuente: World Bank