Hong Kong has been edged out by Seoul as the most expensive city in the region for expatriates, excluding Japan, a worldwide cost of living survey has found. The South Korean capital, which has enjoyed rapid economic growth and investment over the past year, rose 12 places to number 13 with an index of 110 in the twice-yearly study by the Economist Intelligence Unit. The study prices 130 cities around the world to help companies determine expenses for their expatriate executives, with New York used as a basis for comparison with a score of 100. Hong Kong scored 109 and ranked 14, down two places. Top-ranked Tokyo, which has led the index since 1991, as well as Osaka, finally surrendered the distinction of being the world's costliest city to the Norwegian capital, Oslo. 'Despite spending so long at the top, the displacement of Tokyo comes as little surprise. A gradually weakening yen has been compounded by years of low inflation and deflation in the Japanese economy,' the report said. Tokyo slipped to second place while Osaka fell to fourth, behind Iceland's capital, Reykjavik. The rest of the top 10 was little changed and dominated by European cities. Australian cities experienced dramatic increases, with Sydney and Melbourne each rising nine places to numbers 16 and 19, respectively. Auckland, in New Zealand, rose 10 places to 29. Compared to a year ago, when Beijing was the mainland's costliest city with a ranking of 44, the capital now occupies 58th place, behind Mexico City. Shanghai slipped five spots to 51st.