The taxable amount should be in box 2a. If blank and box 2b (not determined) is checked then usually the box 1 amount will be the taxable amount unless you have after tax money in the annuity and the general method is used to determine the taxable amount (assuming that this is a non-qualified annuity with a code D in box 7)
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**