Despite regulations and even a special office dedicated to it, short-term home rentals in San Francisco are largely illegal, according to a new report from the San Francisco Budget and Legislative Analyst’s Office.
The report, issued Thursday, concludes that 1,055 homes, or 26% of entire-home listings in San Francisco, are rented for more than 90 nights per year, which is the maximum allowed for “unhosted” short-term rentals where the home’s full-time resident is not present during the guests’ stay. These homes were rented out for an average of 200 nights, according to the report.
The report also addressed another aspect of San Francisco’s short-term rental regulations: host registrations. Recently, home-sharing company Airbnb shared with city officials that as of March 2016, it has 7,046 hosts in San Francisco. However, the Office of Short Term Rentals, which was established last year to manage and police these rentals, has received only 1,647 registration applications, suggesting that up to 76.6% of Airbnb hosts are out of compliance. Some of these applications can also be from hosts who are listing their homes on websites other than Airbnb, such as VRBO and FlipKey.
Get Data Sheet, Fortune’s technology newsletter.
San Francisco’s Budget and Legislative Analyst’s Office used two sources of data to compile its report. One was data from Airbnb itself, which last week said it will start to share some data publicly. It also used data from Murray Cox, who along with Tom Slee is best known for a recent report on anomalies in Airbnb listings in New York City. Cox “scraped” Airbnb’s website, meaning that he used software algorithms that compiled the publicly available information on Airbnb’s website.
In late 2014, San Francisco passed the current set of short-term rental regulations, which went into effect in February 2015.
Overall, this new report shows that San Francisco’s regulations haven’t been enforced well. One reason for this, according to the report, is the lack of cooperation from services like Airbnb, which could easily provide data to city officials about hosts and listings not compliant with regulations. Another is inadequate regulations and processes. For example, to force hosts to apply to register, the city could mandate home-sharing services to display each host’s registration number. It could also simplify the registration process, something that both the report and Airbnb say is sorely need.
For more on Airbnb, watch:
From an Airbnb spokeswoman:
Airbnb is already working to help meet The City’s goal of fighting illegal hotels and we are taking action by removing unwelcome listings from our platform, releasing data and cracking down on commercial operators. Unfortunately, the registration process remains a challenge — San Francisco is asking hosts to apply for multiple permits, fill out dozens of pages of paperwork and tell The City how many spoons they have in their home.
The typical middle class host in San Francisco shares their space 48 nights a year to generate supplemental income and we are proud that our community is paying their fair share of taxes. We will keep working with City on policies that help keep unwanted commercial activity off the platform and let middle class families share their home so they can afford to stay in San Francisco.
In November, Airbnb successfully defeated a ballot measure that would have imposed stricter regulations on short-term rentals in San Francisco. The company donated more than $8 million to the campaign against the measure.
Shortly after, Airbnb, which since its founding in 2008 has raised $2.4 billion in funding and is currently valued at $25.5 billion, publicly pledged to work more closely with city governments. Since then, it released partial anonymized data about its New York City listings, has begun a pilot to warn Paris-based hosts who might be violating local regulations, and said last week it will begin to remove hosts with multiple entire-home listings in San Francisco.
The story has been updated with comment from Airbnb.