| Año | Valor |
|---|---|
| 1976-01-01 | 41.390728 |
| 1977-01-01 | 47.697368 |
| 1978-01-01 | 45.931759 |
| 1979-01-01 | 34.695817 |
| 1980-01-01 | 40.955631 |
| 1981-01-01 | 38.709677 |
| 1982-01-01 | 36.452005 |
| 1983-01-01 | 40.776699 |
| 1984-01-01 | 34.759358 |
| 1985-01-01 | 31.088083 |
| 1986-01-01 | 29.232040 |
| 1987-01-01 | 41.368821 |
| 1988-01-01 | 41.387373 |
| 1989-01-01 | 39.916260 |
| 1990-01-01 | 39.616175 |
| 1991-01-01 | 39.554140 |
| 1992-01-01 | 39.732685 |
| 1993-01-01 | 38.313120 |
| 1994-01-01 | 36.836735 |
| 1995-01-01 | 28.586279 |
Fuente: World Bank