| Año | Valor |
|---|---|
| 1960-01-01 | 13.183746 |
| 1961-01-01 | 13.033662 |
| 1962-01-01 | 12.476065 |
| 1963-01-01 | 11.891562 |
| 1964-01-01 | 10.912889 |
| 1965-01-01 | 11.073816 |
| 1966-01-01 | 10.877987 |
| 1967-01-01 | 11.528010 |
| 1968-01-01 | 10.273744 |
| 1969-01-01 | 9.514669 |
| 1970-01-01 | 10.019864 |
| 1971-01-01 | 11.168562 |
| 1972-01-01 | 10.639952 |
| 1973-01-01 | 7.177113 |
| 1974-01-01 | 0.773807 |
| 1975-01-01 | 2.401180 |
| 1976-01-01 | 3.568332 |
| 1977-01-01 | 3.510011 |
| 1978-01-01 | 5.050664 |
| 1979-01-01 | 8.649374 |
Fuente: World Bank