| Año | Valor |
|---|---|
| 1980-01-01 | 20.783937 |
| 1981-01-01 | 20.363625 |
| 1982-01-01 | 27.118979 |
| 1983-01-01 | 21.107122 |
| 1984-01-01 | 20.951118 |
| 1985-01-01 | 12.142048 |
| 1986-01-01 | 10.736200 |
| 1987-01-01 | 17.826607 |
| 1988-01-01 | 18.843181 |
| 1989-01-01 | 19.477851 |
| 1990-01-01 | 24.474304 |
| 1991-01-01 | 29.777659 |
| 1992-01-01 | 34.801026 |
| 1993-01-01 | 41.878707 |
| 1994-01-01 | 46.037569 |
| 1995-01-01 | 42.492226 |
| 1996-01-01 | 51.027898 |
| 1997-01-01 | 54.717918 |
| 1998-01-01 | 55.198779 |
| 1999-01-01 | 55.403708 |
Fuente: World Bank