| Año | Valor |
|---|---|
| 1990-01-01 | 6.332808 |
| 1991-01-01 | 6.696594 |
| 1992-01-01 | 6.573399 |
| 1993-01-01 | 6.545220 |
| 1994-01-01 | 6.324215 |
| 1995-01-01 | 6.011984 |
| 1996-01-01 | 5.714182 |
| 1997-01-01 | 5.573048 |
| 1998-01-01 | 5.838159 |
| 1999-01-01 | 6.075550 |
| 2000-01-01 | 7.913111 |
| 2001-01-01 | 7.724638 |
| 2002-01-01 | 6.759166 |
| 2003-01-01 | 6.906495 |
| 2004-01-01 | 7.278813 |
| 2005-01-01 | 7.106169 |
| 2006-01-01 | 7.535359 |
| 2007-01-01 | 7.928076 |
| 2008-01-01 | 8.405738 |
| 2009-01-01 | 8.391510 |
Fuente: World Bank