I'm going to just discuss my Kindle sales because my Nook and Smashwords sales have been minimal--about 100 books on Nook and 10 on Smashwords. (In three months total.)
So I only had about two and a half days of sales in April and I'm sure most of those came from friends. :)
SMS 5 (1 outside the US/UK/Germany so it only makes 35%)
For the US
SMS 105 (2 outside)
For the UK
SMS 633 (17 outside)
Total for the three months and two days: $2522.98
So far in July (as of the 17th) I've sold 2732 copies of WMS and 913 of SMS.
All this is passive income--I wrote the books (and had them professionally edited) 10 years ago.
I'm so very grateful for this experience and I thank every single person who has bought one of my books!