| Año | Valor |
|---|---|
| 1961-01-01 | 13.850000 |
| 1962-01-01 | 14.330000 |
| 1963-01-01 | 15.170000 |
| 1964-01-01 | 15.440000 |
| 1965-01-01 | 15.980000 |
| 1966-01-01 | 16.630000 |
| 1967-01-01 | 17.050000 |
| 1968-01-01 | 18.170000 |
| 1969-01-01 | 18.290000 |
| 1970-01-01 | 19.390000 |
| 1971-01-01 | 19.900000 |
| 1972-01-01 | 21.440000 |
| 1973-01-01 | 22.500000 |
| 1974-01-01 | 23.430000 |
| 1975-01-01 | 25.240000 |
| 1976-01-01 | 26.400000 |
| 1977-01-01 | 25.860000 |
| 1978-01-01 | 25.820000 |
| 1979-01-01 | 26.290000 |
| 1980-01-01 | 29.500000 |
Fuente: World Bank