| Año | Valor |
|---|---|
| 1981-01-01 | 29.490000 |
| 1982-01-01 | 30.180000 |
| 1983-01-01 | 20.990000 |
| 1984-01-01 | 29.030000 |
| 1985-01-01 | 33.450000 |
| 1986-01-01 | 33.720000 |
| 1987-01-01 | 34.970000 |
| 1988-01-01 | 35.640000 |
| 1989-01-01 | 35.920000 |
| 1990-01-01 | 36.830000 |
| 1991-01-01 | 39.740000 |
| 1992-01-01 | 38.220000 |
| 1993-01-01 | 41.150000 |
| 1994-01-01 | 43.890000 |
| 1995-01-01 | 48.690000 |
| 1996-01-01 | 51.010000 |
| 1997-01-01 | 52.260000 |
| 1998-01-01 | 53.430000 |
| 1999-01-01 | 53.830000 |
| 2000-01-01 | 56.400000 |
Fuente: World Bank