| Año | Valor |
|---|---|
| 1996-01-01 | 7.936071 |
| 1997-01-01 | 6.919108 |
| 1998-01-01 | 5.875709 |
| 1999-01-01 | 6.397507 |
| 2000-01-01 | 5.816703 |
| 2001-01-01 | 5.948298 |
| 2002-01-01 | 4.501316 |
| 2003-01-01 | 5.435329 |
| 2004-01-01 | 5.465435 |
| 2005-01-01 | 6.406499 |
| 2006-01-01 | 9.372048 |
| 2007-01-01 | 12.754048 |
| 2008-01-01 | 13.907561 |
| 2009-01-01 | 16.973119 |
| 2010-01-01 | 16.385771 |
| 2011-01-01 | 14.539543 |
| 2012-01-01 | 14.294010 |
| 2013-01-01 | 13.178062 |
| 2014-01-01 | 12.337399 |
| 2015-01-01 | 11.912609 |
Fuente: World Bank