Non-Deductible Basis Form 8606 Reduced by Roth Conversion?

Since 2017 I have contributed the maximum IRA amount and immediately converted to Roth (in 2017 I made two contribution, one for 2016 and one for 2017).  All contributions have been non-deductible and I have zero balances in any traditional IRA, SEP, or SIMPLE plan.  Does the roth conversion reduce the non-deductible basis on form 8606 or should all the contributions (even though they have been converted to roth) be included in the basis?

 

I believe my form 8606 had indicated zero on line 2 for a couple years and then all of a sudden it began showing a cumulative amount. I'm just trying to figure out what is right and how to correct it.

 

My non-deductible contributions are as follows:

 

2016- 5500 (immediately fully converted to roth)

2017- 5500 (immediately fully converted to roth)

2018- 5500 (immediately fully converted to roth)

2019-6000 (immediately fully converted to roth)

2020-6000 (immediately fully converted to roth)

2021- 6000 (immediately fully converted to roth)

 

should my current nondeductible basis be $0 or 34,500

 

Thanks in advance for any insight you can provide!