Conversation so far:
when did el salvador switch to the dollar
The country adopted the US dollar as its currency in 2001.
what was El Salvador's currency before adopting the US dollar
Previously, its national currency was the El Salvadoran Colon and one colon was equal to 100 centavos.
how long did El Salvador use the colon
El Salvador used the colon currency from 1892 to 2001.

Question: why did they change it
Self-contained rewrite: why did El Salvador change their currency