| Año | Valor |
|---|---|
| 1970-01-01 | 0.008900 |
| 1971-01-01 | 0.008700 |
| 1972-01-01 | 0.009500 |
| 1973-01-01 | 0.010800 |
| 1974-01-01 | 0.011900 |
| 1975-01-01 | 0.015300 |
| 1976-01-01 | 0.019600 |
| 1977-01-01 | 0.022600 |
| 1978-01-01 | 0.027200 |
| 1979-01-01 | 0.025800 |
| 1980-01-01 | 0.025100 |
| 1981-01-01 | 0.025300 |
| 1982-01-01 | 0.020500 |
| 1983-01-01 | 0.021900 |
| 1984-01-01 | 0.020900 |
| 1985-01-01 | 0.020600 |
| 1986-01-01 | 0.021600 |
| 1987-01-01 | 0.024800 |
| 1988-01-01 | 0.025200 |
| 1989-01-01 | 0.025500 |
Fuente: World Bank