Well, how do you define a UFO? Do you include blocks that you received in an exchange? If you do that will add about 4 to my count. Then there are the class projects that are not finished when you take the class.....oh, the BOMs that I have participated in. There should be a month added to BOM projects that is assembly the top month.
I thought about doing this a year or so ago and decided I really didn't want to know.