ZURICH has become the world’s most expensive city to live in, according to the latestWorldwide Cost of Living Survey from the Economist Intelligence Unit, our sister company. The strengthening of the Swiss franc in the past year helped lift the city four places up the table to displace Tokyo at the top. The index measures the cost of an expatriate lifestyle in over 130 cities using a weighted average of the prices of 160 products and services. New York’s figure is set to 100 to provide a base for comparisons. The relative strengths of currencies and economies are reflected in changes to the rankings. Thus Sydney has moved from 71st to 7th since 2001, while New York has fallen from 7th to joint 47th.