(Photo by Lauren Gilger - KJZZ)

A Phoenix home listed for rent on Airbnb.

A new report by Pennsylvania State University's School of Hospitality Management found the majority of Airbnb's revenue comes from commercial operators.

Airbnb refers to its business partners as "hosts." Their hosts list spaces for rent on Airbnb's website. Guests book the spaces, and Airbnb keeps a cut of the rent before paying the hosts.

According to a company study, the average host in Arizona is 45 years old and makes about $4,000 a year off rentals. But Dr. John O’Neill, one of the Penn State study’s authors, said many hosts are operating as commercial landlords, renting more than 60 days a year, and some are renting several units.

“Multi-unit operators accounted for only 14 percent of hosts in Phoenix, but drove over 40 percent of the revenue in the city, generating more than $17 million last year," he said.

In a written response, Airbnb said the study was intended to mislead and manipulate, and the vast majority of their hosts are middle-class people sharing their homes in order to create supplemental income.

The Arizona Lodging and Tourism Association said its members have no problem with occasional renters, but want what they call ‘"illegal hotels" to follow the same rules they do - like collecting taxes and meeting fire and safety regulations. Airbnb said it has been collecting and remitting taxes on behalf of its hosts since July 2015.

According to the Penn State study, these five Valley zip codes have the most Airbnb rentals and accounted for nearly $8 million, or 19 percent, of Airbnb's revenue in the metro area between October 2014 and September 2015:

 85251 -Scottsdale, Las Viviendas, Desert Cove, Waterfront  

 85254 - Greenway Park, Cactus Glen, Desert Trails 

 85260 - Northsight, Encata, Sundown Vista 

 85281 - Tempe, University Heights, Lindon Park 

 85006 - Coronado, Avalon, Kenwood