| Año | Valor |
|---|---|
| 1980-01-01 | 25.020559 |
| 1981-01-01 | 25.494416 |
| 1982-01-01 | 25.994352 |
| 1983-01-01 | 26.518785 |
| 1984-01-01 | 27.066567 |
| 1985-01-01 | 27.635269 |
| 1986-01-01 | 28.228614 |
| 1987-01-01 | 28.839932 |
| 1988-01-01 | 29.470845 |
| 1989-01-01 | 30.120445 |
| 1990-01-01 | 30.798517 |
| 1991-01-01 | 31.506016 |
| 1992-01-01 | 32.234060 |
| 1993-01-01 | 32.751275 |
| 1994-01-01 | 33.297978 |
| 1995-01-01 | 33.873203 |
| 1996-01-01 | 34.477151 |
| 1997-01-01 | 35.107825 |
| 1998-01-01 | 35.770048 |
| 1999-01-01 | 36.455942 |
Fuente: World Bank