[sbacic]

Not all that unusual really. Before the EURO replaced the DM, many things in Croatia, such as cars and real estate were denominated in DM. This was due to rampant inflation (especially in the 80s and 90s) causing people to lose faith in the local currency.

[avrionov]

The big difference is that Bulgaria has a currency board, which was agreed to with the International Monetary Fund and the World Bank. This was done to stabilize the exchange rate and the economy in 1997. The exchange rate has been fixed for the last 24 years.