Home prices in the United States between April and June of this year were at their least affordable point since the third quarter of 2008, according to a report by the housing analytics company ATTOM Data Solutions.

In its U.S. Home Affordability Report, ATTOM Data Solutions set its affordability index at 95. An index above 100 indicates that home prices are more affordable than the historic average, while lower figures show that prices are less affordable.

ATTOM Data Solutions determines its affordability index based on the percentage of average wages needed to afford a market's median-priced home. This assumes a 30-year fixed rate mortgage and a 3 percent down payment, as well as costs such as property taxes, homeowners insurance, and private mortgage insurance.

The figure for the second quarter of 2018 was down from 102 in the first quarter of the year and 103 in the second quarter of 2017. This marked the lowest point since the third quarter of 2008, which had an affordability index of 86.

Daren Blomquist, senior vice president of ATTOM Data Solutions, said rising mortgage rates are creating an increasingly pressing affordability concern for buyers. According to Freddie Mac, the average rate on a 30-year fixed rate mortgage was at or above 4.5 percent for much of the second quarter. In the second quarter of 2017, the typical rate hovered around 4 percent, which itself was up above half a percentage point from the second quarter of 2016.

"Slowing home price appreciation in the second quarter was not enough to counteract an 11 percent increase in mortgage rates compared to a year ago, resulting in the worst home affordability we've seen in nearly 10 years," said Blomquist. "Meanwhile, home price appreciation continued to outpace wage growth, speeding up the affordability treadmill for prospective homebuyers even without the rise in mortgage rates."

The nationwide median home price was $245,000, a year-over-year gain of 4.7 percent. This slowed from a median annual growth of 7.4 percent in the first quarter of the year, but continued to outpace the average annual growth of weekly wages, which stood at 3.3 percent.

The average worker would spend 31.2 percent of their wages to buy a median priced home during the quarter. This was above the historic average of 29.6 percent.

Since the first quarter of 2012, median home prices have grown by 75 percent. In the same time period, average wages have increased by only 13 percent.

ATTOM Data Solutions looked at 432 counties across the nation for the report. Home prices were growing faster than wages in 64 percent of all markets.

Each of the eight counties in Connecticut, as well as all three counties in Rhode Island, was considered more affordable than historic norms.

In New London County, ATTOM Data Solutions set an affordability index of 109. The company determined that the average wage of $54,366 was 2.6 percent higher than in the second quarter of 2017, while the median home price was up 6.8 percent to $229,000. In these circumstances, a person earning the average wage would need to dedicate 37 percent of their income to buying a median-priced home.

Genesee County in Michigan, which includes Flint, had the lowest affordability index at 70. Two counties in the Denver metro area—Denver County and Adams County—had the next least affordable indexes at 72 and 73, respectively. Santa Fe County in New Mexico had an index of 73, while Wilson County in the Nashville, Tenn. area had an index of 75.

Travis County, Texas, which includes Austin, was the least affordable among the counties with a population of at least 1 million, posting an affordability index of 77. The Bay Area of California also accounted for a number of low affordability indexes, including Alameda County (81), Santa Clara County (82), and San Francisco County (83). Oakland County in Michigan, which includes Detroit, had an affordability index of 82.

In four counties, median-priced homes were not available on an average worker's salary. These included Marin County, Calif., which where a median home would require 133.2 percent of the average wages; Kings County, N.Y. (123.1 percent), Santa Cruz County, Calif. (121.5 percent); and Monterey County, Calif. (100.3 percent).

On the other end of the spectrum, the average worker in Wayne County, Mich., which includes Detroit, would need to spend just 13.5 percent of their income to afford a median-priced home. This was followed by Clayton County, Ga. (13.7 percent), Rock Island County, Ill. (15.8 percent), Richmond County, Ga., and Saginaw County, Mich. (both 16.4 percent).

ATTOM Data Solutions determined that a person with the average wage in three-quarters of the 432 counties included in the report would not be able to afford a median-priced home based on the affordability specifications of a 3 percent down payment and a maximum debt-to-income ratio of 28 percent.