If you look back you will even see the debt was increasing during the "surplus" years. It's just our governments clever way of keeping things off the books like the borrowing against the SS fund, or maybe even Area 51
Yep. Just move things off-budget. It's government accounting, which is how we can be all warm and fuzzy about our $492 billion budget deficit and still be another $600 billion or so in hock at the end of the year.
Another thing which may be throwing it off is the Social Security trust fund. Used to be it returned a surplus, which we borrowed, in order to have a balance capable of meeting all its obligations. With fewer people working and wages down, it's now drawing money back to meet those obligations, which adds to the debt but might not be counted in the budget deficit.