For the past 11 years my CSA 1099R Taxable Amount has been the exact same amount (~$3,200) less than the Gross Distribution. However, in 2019, my Gross Distribution was reduced due to a court ordered apportionment and the taxable amount was not determined and shown as "Unknown" in box 2a.
Can I assume the same annual reduction to the Gross Distribution (~$3,200) and split it proportionally based on my reduced Gross Distribution to the total. And then reduce the result from my Gross Distribution to show the taxable amount?