Effective Tax Rate on 2023 Taxes, not added up

Hi - I need some help. I am reviewing my 2023 Jt Return for NJ. We have a Taxable Income of $76,713, which should put our Effective Tax Rate somewhere between 10 & 12%, using the progessive taxing method (Our taxable income falls within the 12% bracket). However, the Effective Tax Rate on our return shows only 6.15%. Our Total Tax was $6520.00. If you divide that by the taxable income, you get 8.5%...still doesn't make sense because it's below 10%.  I am confused! 

 

All figures are here: 

Taxable Income -              76,713

Total Tax -                              6520

Total Payments/Credits -   2169

Payment Due -                    4351

Penalty/Int -                             93

Bal Due w/ Penalty/Int -    4,444.00

Effective Tax Rate -            6.15%

 

Again, if our Taxable Income is 76,713 and we fall in the 10-12% bracket, how is TT calculating 6.15%??

 

Thank you in advance for helping me understand how the numbers are calculated. 

Ultimately, I am trying to calculate our Estimated 2024 income.