Housing prices in Sofia have jumped by 11.3 percent, according to a survey conducted by Knight Frank. The increase puts the Bulgaria capital in the top 20 of 150 cities from around the world that have reported steep rises on their housing markets. Sofia ranked 18, ahead of San Francisco and the Dutch city of Utrecht. A number of European cities were also among the top 20, including Budapest, Frankfurt, Rotterdam, Edinburgh, Porto, Berlin and Dublin. The city of Surat in western India topped the list. Housing there has increased by 22.3 percent, according to Knight Frank.