The return-to-office in the wake of the pandemic has happened in fits and starts, but a consistent theme is that offices are far less full than they once were.

While building swipe data from Kastle Systems has shown that office occupancy nationally is still less than half of the pre-pandemic average, a new analysis by proptech firm Density shows how spaces inside the office themselves are being used — or, rather, hardly used at all.

Density analyzed 500,000 working hours in roughly 2,000 workplaces across 13 cities and found that 71% of office spaces can accommodate four times more users than they do today, it said in a release.

Some anecdotal findings from the study: an $87K conference room that sat empty 80% of the time, 100-person social spaces largely used by just three people, and a 22-person meeting room usually occupied by a single person.

The findings show that many of these spaces are primed to be either used differently going forward or redesigned. Density published the findings as it launched a new app, Density Atlas, that tracks office usage for corporate users measuring their RTO plans.

“Buildings are broken. Historically, we have designed and used buildings based on observation, surveys and precedent,” Density CEO Andrew Farah said in a statement. “Many companies rely on outdated, anecdotal data — or no data at all — to make real estate decisions, despite it being their second biggest expense after payroll. That shouldn’t be acceptable in 2022."

Density Atlas uses anonymous-by-design sensors to gather data on buildings and their real estate performances, Yahoo Finance reports. The technology mainly focuses on helping companies identify if their employees perform best in a focus space or a collaborative space.

As companies continue to push their workers to come back to their desks with more frequency, the quality and design of office spaces has taken on greater importance. Newer buildings are drawing more and more office leases as older buildings, seen as less appealing for workers who can choose to stay at home, are facing a reckoning on their future.