Residential condominium and apartment building is leading the U.S. construction recovery, based on a new study released Tuesday.

Property and construction consultatation company Rider Levett Bucknall released its inaugural North American RLB Crane Index, which tracks the number of fixed cranes on construction sites in markets including Honolulu.

Honolulu had 16 construction cranes in November, up from 13 in August. Half the cranes were for residential projects, a third were for commercial projects and the remainder were for healthcare and hospitality projects.

The commercial, healthcare, hospitality and education sectors are beginning to experience increases in crane activity, the report found.

“Unlike other forms of data, cranes are observable and recognizable icons of major construction activity,” said Julian Anderson, president of Rider Levett Bucknall North America, in a statement. “Therefore, they are an extremely useful measure of the changing pace of the construction industry. We’ve always seen them rising in major cities. Now, with the RLB Crane Index, we have an interesting new way to quantify this information and turn it into a metric that is useful to our clients and industry leaders across the continent.”

The company’s local offices in Boston, Chicago, Denver, Honolulu, Los Angeles, New York, Phoenix, San Francisco and Seattle physically counted all fixed cranes appearing on each skyline and gathered additional data and information for the index.

For the inaugural study crane counts were taken in each city on August 1, 2014 for a baseline, and again on November 1, 2014.

The RLB statement did not reveal the estimated cost of the crane count study.