I'm entering 3922 info for ESPP stocks sale, which were purchased over several years with different discount rates offered by employer. How do I enter such info?

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?