| Año | Valor |
|---|---|
| 1990-01-01 | 4.154391 |
| 1991-01-01 | 4.313991 |
| 1992-01-01 | 4.404888 |
| 1993-01-01 | 4.604803 |
| 1994-01-01 | 4.781204 |
| 1995-01-01 | 3.709892 |
| 1996-01-01 | 3.622358 |
| 1997-01-01 | 4.093647 |
| 1998-01-01 | 3.701485 |
| 1999-01-01 | 3.552646 |
| 2000-01-01 | 3.414709 |
| 2001-01-01 | 3.185233 |
| 2002-01-01 | 3.266342 |
| 2003-01-01 | 3.316859 |
| 2004-01-01 | 3.409770 |
| 2005-01-01 | 3.412984 |
| 2006-01-01 | 3.464984 |
| 2007-01-01 | 3.615532 |
| 2008-01-01 | 3.671893 |
| 2009-01-01 | 3.751025 |
Fuente: World Bank