PORTLAND — A national report found 98 percent of Maine’s fatal car crashes occurred on rural, non-interstate roads in 2012 as the amount of rural road pavement in poor condition rose about 9 percentage points from three years prior. The percentage of deficient rural bridges rose one point from the 2009 report.

The latest rural road assessment released Thursday from Washington, D.C.-based nonprofit research group The Road Information Program, or TRIP, found 161 of 164 fatal Maine crashes happened on rural roads in 2012, compared with 137 of 159 fatal crashes, or 86 percent, in 2009.

Maine ranked far higher than the national average — around 50 percent — both years but jumped from fourth to the highest state in the country for the share of vehicle fatalities that occurred on rural roads.

While Maine far outpaced the national average and the next-highest North Dakota — 81 percent — for the share of all fatal crashes on rural roads, it does not mean Maine roads were the nation’s most dangerous. The TRIP report estimated Maine had two fatalities for every 100,000 miles traveled on rural roads in 2012, placing it 26th nationally. That’s half the rate of South Carolina, which had the deadliest rural roads in that year.

By contrast, Maine had the safest interstate in the country, with just 26 deaths per 100,000 miles traveled on urban roads and the interstate. For all roadways, Maine placed 26th by that measure.

Maria Fuentes, executive director of the Maine Better Transportation Association, said rural road quality is a “huge issue” every state is facing.

“There is data that shows there are more accidents on rural roads that aren’t in good shape,” Fuentes said in a phone interview. “So it’s a safety issue, and it’s an economic issue. And I think it’s something that impacts every person in the state.”

Fuentes said the problem has been exacerbated in recent years by gridlock in Washington, D.C., echoing a statement of TRIP’s latest rural roads report that calls on the federal government to boost funding for the federal Highway Trust Fund.

If Congress doesn’t allocate more money to the fund by Oct. 1, a cash shortfall projected by the Congressional Budget Office could mean $196 million in cuts to highway and transit improvements in Maine, the report states.

“The impact of inadequate federal surface transportation revenues could be felt as early as this summer, when the balance in the Highway Account of the federal Highway Trust Fund is expected to drop below $1 billion, which will trigger delays in the federal reimbursement to states for road, highway and bridge projects, which would likely result in states delaying numerous projects,” the report states.

Fuentes said lagging federal funding is matched with decreased investment at the state level. In the 1970s, she said, about 26 percent of state revenues went to transportation; that figure is now closer to 10 percent.

“With the federal government not being the partner that they once were with the states, states are having to figure out on their own how to maintain their system, and it’s been very difficult,” she said.

Jim Hanley, who handles government relations for Westbrook-based Pike Industries and is president of the Maine Better Transportation Association, said in a statement the rising percentage of rural road pavement in poor condition harms Maine’s economy.

“Every year [Maine Department of Transportation] posts more than 2,000 miles of state roads for months in the spring, and that has a profound effect on our rural economy — inhibiting the movement of goods and services and putting the public safety at risk,” Hanley said.

In 2012, a TRIP report estimated Mainers paid between $299 and $526 per year for car repair costs because of bad roads — a rise from October 2009.

According to the group’s website, its funders include businesses involved in highway and transit engineering and construction, insurance companies, equipment manufacturers, distributors and suppliers and others it says are concerned “with an efficient and safe surface transportation network.”

The latest report also points to agriculture as an industry bearing the brunt of bad roads. Earlier this year, USDA data showed the number of Maine farms is on the rise.

“Certainly local farming is an area in which we’re really seeing some very positive growth,” Fuentes said. “But we’re not giving them the support in terms of the transportation network that we should be.”

Ted Talbot, spokesman for Maine’s transportation department, said he couldn’t comment on road conditions broadly without knowing which roads the TRIP study identified as being in poor condition. In its three-year work plan, released in January, the department estimated funding for its core highway and bridge programs will fall about $100 million short per year.

Rocky Moretti, TRIP’s director of policy and research, said in an email the group’s data “does not include any additional data on actual bridges or roads,” but its pavement data includes rural arterials, or high-capacity roads, and collectors, which are low-to-moderate capacity roads.

While the latest report gives a general overview of the condition of rural roads in the state, Fuentes said her organization will get more specific next week, revealing its choice for the “Worst Road in Maine Contest.”

As for bridges, the report found 16 percent of the state’s rural bridges were structurally deficient, compared with 15 percent in 2010. The study is one of many issued on infrastructure quality each year.