BOSTON — In Tokyo, office space costs $216 per square foot annually - easily eclipsing 69 other cities surveyed by Colliers International, a Boston-based real estate company.Part of the reason for the high price may be a shortage of space: Tokyo also has the lowest vacancy rate of the 70 cities surveyed - 0.5 percent. Following Tokyo in the survey were London ($94), Singapore ($61), Paris ($60), and Hong Kong ($52). In the United States, the most expensive office space was in New York ($37), followed by Washington, D.C. ($34), Los Angeles ($29), Chicago ($28), and San Francisco ($26). The lowest vacancy rate was Louisville, Ky., with 7 percent. Of the 70 cities, Denver, Phoenix, and Darwin, Australia had the least costly office space, at $13 per square foot.