Statisticians have pushed their analytical powers to the limits to explain this week’s encouraging report from the National Highway Traffic Safety Administration.

Highway deaths last year were the fewest since 1961, the year cosmonaut Yuri Gagarin became the first human in orbit.

What’s the cause behind such a stunning effect?

Well, some say it’s the economy. It collapsed as gasoline prices soared, giving budget-conscious motorists a double incentive to curb their driving.

OK, but the NHTSA figures are raw numbers, so you have to think about the growth in both population and numbers of automobiles on the road in the past 40-plus years to fully appreciate what a safety accomplishment this is. Calculated as a ratio of deaths per 100 million miles traveled, the figure for 2008 was 1.28, the lowest ever.

Meanwhile, the NHTSA reported a relevant companion statistic: Seat belt use nationwide was a record 83 percent.

There are too many variables to allow clear cause-and-effect relationships behind these numbers. The aforementioned economy, along with such factors as law enforcement practices, public education programs and improved vehicle safety engineering, no doubt contributed.

But the correlation between rising seat belt use and declining traffic fatalities is too compelling to ignore. Who knows, increasing attention by state lawmakers to such safety concerns as cell phone use probably deserves some credit, too.

But in both of those cases, legislative efforts have met with predictable resistance from segments of the public who object to government’s intrusion into their private decisions. The achievements reflected in this week’s report offer a strong rebuttal to those objections.

The NHTSA noted in its report that states’ seat belt usage experience is better when enforcement is stronger. That seems intuitive, but to validate it, consider the experiences of Washington and Idaho.

In Washington, where failure to wear a seat belt is a primary offense – meaning that alone is cause for an officer to pull you over – the usage rate is 96.5 percent, third best in the nation. In Idaho, it’s a secondary offense, so you can be cited only if you were pulled over for another reason. Idaho ranked 39th in the nation at 76.9 percent, the second straight year of decline.

In Washington, a violation can bring a three-digit fine. In Idaho, an adult driver can be fined only $10 – up to $51.50 if the driver or an unbuckled passenger is under 18.

Many Americans still feel government is overregulating their lives, and at times it probably is. But the concern is overcome when government can demonstrate, as these numbers do, that it is helping to save their lives.