| Año | Valor |
|---|---|
| 1990-01-01 | 9.868800 |
| 1991-01-01 | 10.078600 |
| 1992-01-01 | 10.323500 |
| 1993-01-01 | 10.535900 |
| 1994-01-01 | 10.826800 |
| 1995-01-01 | 11.045000 |
| 1996-01-01 | 11.306700 |
| 1997-01-01 | 11.592200 |
| 1998-01-01 | 11.938500 |
| 1999-01-01 | 12.391300 |
| 2000-01-01 | 13.079100 |
| 2001-01-01 | 12.415200 |
| 2002-01-01 | 12.648200 |
| 2003-01-01 | 12.980600 |
| 2004-01-01 | 13.300900 |
| 2005-01-01 | 13.725000 |
| 2006-01-01 | 14.198100 |
| 2007-01-01 | 14.737700 |
| 2008-01-01 | 15.265600 |
| 2009-01-01 | 15.967700 |
Fuente: World Bank