@delta_hotel - 7B is not the correct code. it's going to be a "T" or a "Q" when you get the form next year.
since you are over 59.5 but the Roth has not been open for 5 years, only the earnings are subject to tax. the IRS presumes that ALL the contributions are distributed before ANY earnings.
it might be easier to just do this by hand
1) how much did you contribute to the Roth IRA over those 3 years?
2) how much was the distribution?
3) 2) - 1) is the earnings and is taxed at your marginal tax rate. if 2) -1) is less than zero, then you didn't withdraw any earnings.
because you are over 59.5. there is no 10% penalty.
