The percentage of home buyers in Los Angeles County who could afford to purchase a single-family home at $557,220 – the median price during the second quarter – fell to 26 percent, according to the Koreatown-based California Association of Realtors’ housing affordability index.

The index indicated an annual income of at least $118,000 annually would be required to afford a monthly payment of $2,950 – including taxes and insurance – on a home at the median price. The calculation assumes a 20 percent down payment and an effective composite interest rate, which takes inflation into account, of 4.7 percent on a 30-year mortgage.

L.A. County’s affordability percentage dipped by two percentage points, and lined up with the statewide rate, which fell three percentage points year over year to also reach 26 percent, according to the index. The median price statewide was $596,730.

The recent rate marked the 21st consecutive quarter that the index was below 40 percent for California. The index hit a peak of 56 percent during the second quarter of 2012.

The study cited rising home prices and mortgage interest rates as factors in the drop in the affordability index.

The effective composite interest rate of 4.7 percent was up from 4.4 percent during the first quarter and nearly 4.1 percent during the second quarter of 2017.

Ventura was the only Southern California county to see improvement – one percentage point – in the affordability index for the $670,000 median price there.

Orange County was the least affordable area with only 20 percent of buyers who made the nearly $176,000 in annual income needed to afford the median home price of $830,000.

San Bernardino County was Southern California’s most affordable area for home buyers. Annual income of at least $61,470 was needed to afford a median home price of $290,000 – making the area affordable to 49 percent of home buyers during the second quarter.

The highest median home price statewide was in San Mateo County, at $1.65 million, with an affordability index of 14 percent of residents. The median home price in neighboring San Francisco County was $1.63 million, also affordable to 14 percent of home buyers.