Follow the I-864 form instructions. For part 6, items 24.a to c on form I-864, copy the Total Income figures exactly as they are listed on your tax return transcripts for the 3 most recent tax years. As in, the actual number on the line that says "TOTAL INCOME".
Your current annual income should be listed on part 6, item 7. This is where you list the income following the calculation advised by @Crazy Cat above. Note that item 24a = PAST income, while item 7 = CURRENT income, so those two items do not have to be equal.