| Año | Valor |
|---|---|
| 1990-01-01 | 2.460531 |
| 1991-01-01 | 2.281158 |
| 1992-01-01 | 2.146342 |
| 1993-01-01 | 1.995835 |
| 1994-01-01 | 1.826961 |
| 1995-01-01 | 1.688915 |
| 1996-01-01 | 1.551244 |
| 1997-01-01 | 1.409914 |
| 1998-01-01 | 1.256032 |
| 1999-01-01 | 1.198405 |
| 2000-01-01 | 1.136870 |
| 2001-01-01 | 1.077244 |
| 2002-01-01 | 1.006191 |
| 2003-01-01 | 0.956046 |
| 2004-01-01 | 0.888439 |
| 2005-01-01 | 0.810696 |
| 2006-01-01 | 0.723510 |
| 2007-01-01 | 0.674824 |
| 2008-01-01 | 0.612140 |
| 2009-01-01 | 0.578580 |
Fuente: World Bank