Again, I would have to see some sort of statistical evidence to ever believe that. It just doesn’t make logical sense.
Most everything I can find refers to number of slaves owned rather than number of owners...I know the southern plantation owners owned many more than their northern brethren, but from what I’ve heard most my life is that many individual slaves were owned in the north as manservants, butlers, cooks etc....
Also, from what I’ve read, this was from the founding of our country in 1776 on up....Not at the time of the War Between the States.