Daily amount of Iron?

I just realized that MFP has set my goal amount for Iron at 100mg. This seems rather (extremely) high, as most things I have read/found/looked into suggest roughly 18mg/day for an adult female.

Did I miss something? Is it posting a percentage and not the amount? (Even this would confuse me as my multivitamin has 18mg of iron in it.)

I know I am doing ok on iron... (or was the last time I went to give blood...) because I use donating blood as a way to check on my iron levels. (It might be sneaky, but they get some blood and I get my iron levels, temp and BP taken, ha!)

Any insight?