Inheritances and gifts from relatives and friends are included there. I would wager that most of the sales are between friends and acquaintances where both parties know that the other owns multiple firearms already.
Yes, gifts and inheritances are covered by the one in five figure. The one in seven figure is for purchases.
Simply put, that's a loophole big enough to drift an eighteen wheeler through sideways and it should be entirely eliminated. It's millions and millions of guns. Background checks for everyone. Period.