| Año | Valor |
|---|---|
| 1990-01-01 | 0.001600 |
| 1991-01-01 | 0.001700 |
| 1992-01-01 | 0.002100 |
| 1993-01-01 | 0.002100 |
| 1994-01-01 | 0.002500 |
| 1995-01-01 | 0.002900 |
| 1996-01-01 | 0.002700 |
| 1997-01-01 | 0.003100 |
| 1998-01-01 | 0.003400 |
| 1999-01-01 | 0.002700 |
| 2000-01-01 | 0.002800 |
| 2001-01-01 | 0.002500 |
| 2002-01-01 | 0.002700 |
| 2003-01-01 | 0.003200 |
| 2004-01-01 | 0.003100 |
| 2005-01-01 | 0.003500 |
| 2006-01-01 | 0.003800 |
| 2007-01-01 | 0.004300 |
| 2008-01-01 | 0.005200 |
| 2009-01-01 | 0.006000 |
Fuente: World Bank