| Año | Valor |
|---|---|
| 1987-01-01 | 0.408567 |
| 1988-01-01 | 0.428149 |
| 1989-01-01 | 0.447731 |
| 1990-01-01 | 0.467313 |
| 1991-01-01 | 0.486895 |
| 1992-01-01 | 0.506477 |
| 1993-01-01 | 0.526060 |
| 1994-01-01 | 0.545642 |
| 1995-01-01 | 0.565224 |
| 1996-01-01 | 0.584806 |
| 1997-01-01 | 0.604388 |
| 1998-01-01 | 0.623970 |
| 1999-01-01 | 0.643552 |
| 2000-01-01 | 0.648518 |
| 2001-01-01 | 0.653484 |
| 2002-01-01 | 0.658449 |
| 2003-01-01 | 0.663415 |
| 2004-01-01 | 0.668381 |
| 2005-01-01 | 0.673346 |
| 2006-01-01 | 0.678312 |
Fuente: World Bank