From thailand-property-guide.com - the number of expatriates in Bangkok with work permits grew to 67,412 in 2006, a 12.5% increase year on year according to statistics by the Alien Occupational Control division of the Department of Employment. Last year there was only a limited amount of new supply in apartments, and there were only about 330 units completed last year. But the number of condominium units grew by over 4,000 units. That will continue to be the case in the next two to three years,”
As for two-tiered pricing for Thais and Foreigners, there really isn’t a Thai rental market. Given that Thais have the freedom to buy and sell what they choose, unlike foreigners, those with high salaries and incomes just won’t go out and rent 75,000 a month apartments. So there is no Thai market above Bt15,000 a month.