How do I enter 3922 information for a period where different ESPP discount rates (5% for a year & 15% for remaining years) were offered by the employer over time?

I sold ESPP stocks purchased from 2004 to 2011. I am entering the 3922 information. TurboTax asked for discount rate at the beginning of step by step process before I enter individual lot details. During the first couple of years the company offered 15% discount and then reduced it to 5%. How do I enter this kind of information in Turbo Tax?