LOS ANGELES—Housing has gotten less affordable in all Southern California counties, compared to a year ago, a real estate group said May 11. Statewide housing affordability reached its lowest level since mid-2018, as higher prices fueled by a shortage of homes for sale pushed the state’s median home price more than 22 percent higher on a year-over-year basis, according to the California Association of Realtors (CAR). The percentage of home buyers who could afford to purchase a median-priced, existing single-family home in California in the first quarter of 2021 dropped to 27 percent from 35 percent in the first quarter of 2020, the organization said. The first-quarter 2021 figure is less than half of the affordability index peak of 56 percent in the first quarter of 2012. Among Southern California counties, Orange County was the least affordable at 20 percent and a median home price of $1 million. Los Angeles …