| Año | Valor |
|---|---|
| 1996-01-01 | 27.889246 |
| 1997-01-01 | 28.403953 |
| 1998-01-01 | 27.860201 |
| 1999-01-01 | 28.107296 |
| 2000-01-01 | 25.000176 |
| 2001-01-01 | 23.144225 |
| 2002-01-01 | 22.308615 |
| 2003-01-01 | 16.337275 |
| 2004-01-01 | 10.326141 |
| 2005-01-01 | 5.344612 |
| 2006-01-01 | 13.409533 |
| 2007-01-01 | 4.188131 |
| 2008-01-01 | 3.664158 |
| 2009-01-01 | 5.375613 |
| 2010-01-01 | 4.861343 |
| 2011-01-01 | 3.496248 |
| 2012-01-01 | 2.659479 |
| 2013-01-01 | 1.937577 |
| 2014-01-01 | 2.048860 |
| 2015-01-01 | 4.243654 |
Fuente: World Bank