Many of California’s largest cities have seen big increases in their homeless population in recent years. San Francisco is among them, showing an increase of 17 percent from 2017. But the reality may be even worse than that.

Another way of counting the city’s homeless population suggests it actually grew 30 percent, which was more than twice as large as the previous tally, the New York Times reports.

The standard method of counting the homeless is called a point-in-time count and involves volunteers walking the city on a single night and counting, to the best of their ability, the number of people sleeping on the streets and in shelters. This method counted 8,011 homeless in 2019.

But consulting a database maintained by the City of San Francisco produces an alarming, but perhaps more comprehensive, total of 17,595 people for the 2019 fiscal year. The database in question keeps a record of homeless people who receive health care and other city social services (those who received multiple services are counted only once).

Looking back at these data, the 30 percent increase seen in the last year is the largest in eight years by a wide margin. The names of more than 1,000 people entered the homelessness databases for the first time in the last fiscal year.

A portion of the uptick may be accounted for by extra effort put into the assessment by the city in 2019, Rachael Kagan, the spokeswoman for San Francisco’s Department of Public Health, told the New York Times.

Homeless populations are always in flux, which makes precise counts nearly impossible, but according to Kagan the higher figures represent the most comprehensive picture of homelessness in San Francisco. But, she added, even this count is likely to be an underestimate: “It does not include people who did not seek services, so it is still an incomplete picture.”