HotPads, an apartment listing site based in San Francisco and owned by Zillow, says that of all the amenities landlords try to use to entice renters in 2017, the most crucial perk is proximity to tech shuttles and buses.

The word “shuttle” pops up in 9.8 percent of HotPads listings, according to the site’s press release.

That doesn’t make it the most popular amenity in the city—words like “concierge” popped up 14.7 percent of the time, while “deck” came up 26.6 percent of the time.

But it stands out because it’s a phrase almost never mentioned in other cities. Only 0.8 percent of ads in the other 19 largest metro areas in the country use it.

This is not necessarily surprising, of course—other cities don’t have San Francisco’s one-two punch of gangbusters tech scene and huge geographic sprawl between the major housing centers and the major job centers.

But that gap of more than 12 times the national average is at least a startling and intriguing benchmark of just how deep Silicon Valley’s fingerprint in San Francisco’s housing scene is; shuttle access has become the most quintessentially San Franciscan of all apartment shopping perks, at least on this platform.

Here’s more of what San Francisco landlords are most likely to toss out to renters those in other cities aren’t:

“Bosch appliances” (nine times more likely)

“Panoramic views” (5.3 times more likely)

“Concierge” (3.26 times more likely)

“Gourmet kitchen” (3.25 times more likely)

“Deck” (1.7 times more likely)

Some of these perks are just more common in San Francisco than elsewhere, while others may instead reflect what San Francisco landlords think most attractive to local renters.

For the curious, here’s some of the least popular terms relative to the national average:

“Basement” (4.5 times less likely)

“Exposed brick” (2.47 times less likely)

“Heaters” (1.34 times less likely)

“Grill” (1.7 times less likely)

“Yard” (1.65 times less likely)

Of course, this poses the question of whether or not HotPads ads represent what San Francisco apartment ads in general say. This turns out to be hard to gauge.

“Shuttle” pops up 9.8 percent of the time on HotPads. By comparison, of 2,500 San Francisco ads on Craigslist right now, 446 of them use the term, about 17 percent overall.

And of 1,182 Bay Area homes on PadMapper, 163 listings (almost all of them in San Francisco) mention shuttles, about 13.7 percent.

On the other hand, on the the site Apartments.com, 2,674 ads mention shuttles 153 times, about five percent of the time.

And of 6,916 apartments listed on ApartmentFinder, only 202 reference the word “shuttle,” a meager two percent.