| Año | Valor |
|---|---|
| 1990-01-01 | 20.165900 |
| 1991-01-01 | 21.302400 |
| 1992-01-01 | 22.377700 |
| 1993-01-01 | 22.486000 |
| 1994-01-01 | 23.946100 |
| 1995-01-01 | 17.027800 |
| 1996-01-01 | 16.893500 |
| 1997-01-01 | 19.927100 |
| 1998-01-01 | 17.080700 |
| 1999-01-01 | 17.393400 |
| 2000-01-01 | 17.350500 |
| 2001-01-01 | 15.961500 |
| 2002-01-01 | 16.454700 |
| 2003-01-01 | 16.999800 |
| 2004-01-01 | 17.053400 |
| 2005-01-01 | 17.407000 |
| 2006-01-01 | 17.435300 |
| 2007-01-01 | 17.876600 |
| 2008-01-01 | 18.515100 |
| 2009-01-01 | 19.143600 |
Fuente: World Bank