Historical Loan-to-value Ratios For USA

Hi!

As part of my thesis, I am conducting an econometric analysis of the housing market in the US.

For this I really need historical LTV data, I am however having a hard time finding it for a longer time period.

The closest I have come is FRED, where they have data back to 2012.

Preferably I would need it back to year 2000 or earlier.

Any help would be greatly appreciated!