 The tallest buildings could also acquire publicity for their owners, in turn making it easier to find and keep the best tenants.Furthermore, the higher the cost of the underlying real estate, the taller a building needed to be to generate a suitable return on the investment, and the minimum sensible commercial height for a skyscraper project grew to between 40 and 45 stories.70 story skyscrapers became relatively common, although an influential 1930 study demonstrated that the best rate of return on a skyscraper was to build it 63 stories high, returning an annual profit of 10.25 percent.