I work outside (for the last 7 years), and when I was tested a couple of years ago I was at 18. 6-8 months of avg. 10,000 IU/day got me up to 36.
I need to get tested again to see where I'm at.
Disclaimer: I live in the Pacific Northwest. Sun? What sun?
"Wait! I'll fix it!"
"Problems always disappear in the presence of a technician."
"If you can't improvise, what are you doing out in the field?"