Increases are higher in several West Coast cities, where the explosion in homelessness has prompted at least 10 city and county governments to declare states of emergency since 2015.

City officials, homeless advocates and those living on the streets point to a main culprit: the region’s booming economy

Rents have soared beyond affordability for many lower-wage workers who until just a just few years ago could typically find a place to stay. Now, even a temporary setback can be enough to leave them out on the streets.