Alik
Level 2

Calculating % business use of home from longer than available records

Sold a home which had business/rental use the percentage of which varied throughout the years.
IRS keep and requires you to keep records for only 7 years (except in special circumstance).
I've owned the home for 23 years.
How do i determine total % business use if I don't have all nearly quarter century of the records?

Note: I am not asking how to find total accumulated depreciation. I know that part. Just the % use for the capital gains <homeowner-exclusion vs. business> allocation.