| Año | Valor |
|---|---|
| 1990-01-01 | 2.897400 |
| 1991-01-01 | 3.230000 |
| 1992-01-01 | 2.943700 |
| 1993-01-01 | 3.546600 |
| 1994-01-01 | 3.426000 |
| 1995-01-01 | 3.535500 |
| 1996-01-01 | 3.804700 |
| 1997-01-01 | 3.370800 |
| 1998-01-01 | 3.548400 |
| 1999-01-01 | 3.816200 |
| 2000-01-01 | 3.864900 |
| 2001-01-01 | 4.013000 |
| 2002-01-01 | 4.179800 |
| 2003-01-01 | 4.032000 |
| 2004-01-01 | 4.912200 |
| 2005-01-01 | 4.638400 |
| 2006-01-01 | 4.808600 |
| 2007-01-01 | 5.181200 |
| 2008-01-01 | 4.846000 |
| 2009-01-01 | 4.804000 |
Fuente: World Bank