The Wealth Report 2015 by Knight Frank reported that 24 individuals in Indonesia in 2014 had wealth at least US$1 billion and 18 live in Jakarta. The cost of living continues to rise. Both land price and rents have become expensive. Mercer's ''2017 Cost of Living Survey'' ranked Jakarta as 88th costliest city in the world for expatriates. Industrial development and the construction of new housing thrive on the outskirts, while commerce and banking remain concentrated in the city centre. Jakarta has a bustling luxury property market. Knight Frank, a global real estate consultancy based in London, reported in 2014 that Jakarta offered the highest return on high-end property investment in the world in 2013, citing a supply shortage and a sharply depreciated currency as reasons.