Still in awe over Anne Tyler's intense revision process

I was just reading the excellent interview with Anne Tyler at BarnesandNoble.com, and was blown away by this:

BNR: How many drafts did you make of Noah's Compass? Was that more or less on par with the number of drafts you've made for other novels? Did any of your
books come relatively easy, from beginning conceit to finished product?

AT: It all depends on how you count, but I'd say the book took four
drafts. That's three longhand drafts before I entered it in the computer, and
then I copied the...