Here’s something that defies explanation: The proportion of Americans who now believe there are too many government regulations has just fallen to the lowest level since Barack Obama took office.

Now, what could possibly explain such a dramatic drop?

Obama loved government regulations. The Illinois Democrat rarely encountered a new government rule that he did not like.

During the Obama reign of error, the Gallup people found that the percentage of Americans who said there was “too much regulation” on business and industry soared from the average of 37 percent during the eight years of the George W. Bush presidency to a whopping 48 percent during the 18 Obama years. OK, it just seemed that long.

So now after but 21 months of the Trump presidency, only 39 percent say there are too many regulations. Thirty-three percent say there’s about the right amount. And a quarter say we need more government regulations.

You might suspect the growing approval of the amount of government regulation has some connection to an oft-repeated campaign promise by Donald through 2015-16.

Upon taking office, he ordered that two regulations be rescinded for every new one instituted. The result has been the elimination of hundreds of government rules, most of them laid down by the Obama administration.

So many, in fact, that Trump bragged, “No president has ever cut so many regulations in their entire term … as we have cut in less than a year.” That might sound too good to be true. Because it is.

Nonetheless, the combination of fewer official restraints out of Washington and the major tax cut legislation Trump signed last December has boosted business confidence such that the economy has been growing at a 4.2 percent annualized rate with historically low unemployment, especially among blacks and Hispanics.

In recent midterm campaign speeches, Obama has claimed that he actually began the booming economic recovery.

So, it’s left to individual Americans to decide by Nov. 6 whom to credit based on the evidence at hand — Republicans who passed the tax cuts and cut regulations or Democrats who vow to kill the tax cuts and restore more regulations.

We sure can’t figure it out. Maybe you can.