| Año | Valor |
|---|---|
| 1990-01-01 | 2.417500 |
| 1991-01-01 | 2.499300 |
| 1992-01-01 | 2.545000 |
| 1993-01-01 | 2.628000 |
| 1994-01-01 | 2.750700 |
| 1995-01-01 | 2.848200 |
| 1996-01-01 | 2.904400 |
| 1997-01-01 | 3.005300 |
| 1998-01-01 | 3.118100 |
| 1999-01-01 | 3.209900 |
| 2000-01-01 | 3.367100 |
| 2001-01-01 | 3.262100 |
| 2002-01-01 | 3.348600 |
| 2003-01-01 | 3.469300 |
| 2004-01-01 | 3.563500 |
| 2005-01-01 | 3.705800 |
| 2006-01-01 | 3.836300 |
| 2007-01-01 | 3.954500 |
| 2008-01-01 | 4.061800 |
| 2009-01-01 | 4.192100 |
Fuente: World Bank