Traffic fatalities in Minnesota and the nation are on the rise after six years of steady declines.

An estimated 25,580 people died in motor vehicle crashes in the United States during the first nine months of this year, up from 23,884 during the same period last year, according to a report by the National Highway Traffic Safety Administration (NHTSA).

The 7.1 percent jump represents the largest such increase during the January-through-September period since 1975, the first year federal officials started collecting traffic death data.

NHTSA officials emphasized that the year-to-year comparison between this year and last was made against 2011 figures that show that the number of people killed on the nation's roads fell to a 60-year low. Even with the significant increase this year, the number of people killed on the nation's roads during the first nine months of the year has fallen 26 percent since 32,141 people died in that time period in 2005. Since then, the number of deaths reported during the first three quarters of the year declined annually until this year.

One reason for the uptick might be that Americans drove more in the first nine months of 2012 than they did the previous year. The number of vehicle miles traveled between January and September increased by 14.2 billion miles, or 0.6 percent, according to the report. But agency officials said that it was too soon to say why the number of deaths went up this year and that they are still studying the data collected from authorities in all 50 states, the District of Columbia and Puerto Rico.

"There is a relationship between the economy, gas prices, driving and fatalities," Jonathan Adkins, deputy executive director of the Governors Highway Safety Association, told the Washington Post. "However, the increase can't be explained solely because of an improving economy and more discretionary driving. Vehicle miles of travel likely didn't increase that much in 2012. Other factors may be at play. For example, 2012 had one of the warmest winters on record. That may have resulted in a longer motorcycle riding season and more pedestrian activity and, hence, more fatalities."

The report did not break out numbers by state.

In Minnesota, there have been 366 deaths to date this year, compared with 338 at the same time last year, according to the Department of Public Safety's Office of Traffic Safety. That is just two shy of the 368 killed on state roads in 2011, which was the first time the state has recorded fewer than 400 deaths since 1944. If three or more deaths are reported before the end of the year, 2012 would mark the first year that there would be a year-to-year increase in the past five years.

Deaths fell from 510 in 2007 to 455 in 2008. In 2009 there were 421 and in 2010 there were 411. Minnesota's 10 percent decrease from 2010 to 2011 was among the highest in the nation and exceeded the national average of 1.9 percent, according to the NHTSA.

Overall, 32,367 people died on the nation's roads in 2011, which was the lowest total since 1949, when there were 30,246 deaths. Along with Minnesota, 36 states showed a decrease in the number of fatalities, while 14 states along with the District of Columbia and Puerto Rico showed increases.

The 7,580 fatalities on the nation's roads the first quarter of 2012 represented a 13 percent jump from 2011. There were 8,600 deaths from April to June, an increase of 4.7 percent, and 9,400 were reported from July to September, an increase of 4.9 percent.

Tim Harlow • 612-673-7768 Twitter: @timstrib