Because I am a freak, I can tell you that I'm averaging a speed of 38 words per minute on my new WIP.
I am not a friend of numbers, but for some reason I love keeping track of things in Excel spreadsheets. I got into the habit during NaNoWriMo, because writing 50,000 words in 30 days is all about numbers -- the minimum amount to write each day, and for me, how much to catch up/get ahead, because I've never been the type to write every single day. (Though I really should!)
My spreadsheet tracks time in minutes, total words, words in that particular writing session, the date, and how many words I've done on that day if I've written in more than one block of time. New for this WIP I've added a column for percent done, since it's not NaNo and I don't have a handy progress bar to keep track. And I added the WPM column just for fun.
The last thing I worked on, I kept up the same format when I was editing the first draft to the second. In that case, the word count got smaller as I trimmed the fat.