| Año | Valor |
|---|---|
| 1990-01-01 | 35.916438 |
| 1995-01-01 | 40.603692 |
| 2000-01-01 | 48.903485 |
| 2005-01-01 | 63.331034 |
| 2010-01-01 | 69.240782 |
| 2011-01-01 | 58.778872 |
| 2012-01-01 | 52.016582 |
| 2013-01-01 | 47.716041 |
| 2014-01-01 | 39.245224 |
| 2015-01-01 | 30.142331 |
| 2016-01-01 | 23.261059 |
| 2017-01-01 | 24.512301 |
Fuente: World Bank