As a heat wave wallops the Pacific Northwest, one piece of data takes on new meaning: the percent of air-conditioned housing units.

Seattle is the least air-conditioned MSA in the United States, according to Census data, although the percent of homes with AC units has increased substantially in recent years.

More on the data from the Seattle Times:

For sure, Seattle is still the least air-conditioned metro area. But as of 2019, which is the most recent data, 44% of homes here are now air-conditioned — an increase of more than 10 percentage points in four years.

In 2015, about 487,000 homes were air-conditioned by either central air or window units in King, Pierce and Snohomish counties. As of 2019, that number jumped by around 250,000 and now stands at 676,000. The number of non-air-conditioned homes has declined by more than 100,000.

If this trend continues, it won’t be long before the unimaginable happens: The majority of homes in the Seattle area will be air-conditioned.