One of the most prevalent arguments against is that rent control may hurt new construction and supply. Yet, two of New York City's greatest housing construction booms in the 20th century occurred during periods when strict rent control policies were in effect. The first was from 1921 through 1928, when more than 665,000 units were added, and again from 1947 through 1965, when more than 676,000 units were added. A change in the city's zoning laws caused a sharp decline in new construction in the late 1960s.