1OOO MSV is indeeed 100 Rem! In the USA, ppl get through the year, 6.2 MSV, which is 620 Rem. Read the math here: http://en.wikipedia.org/wiki/Sievert#SI_multiples_and_conversions
No it is 620mRem. I am wrong that 620 would kill you spread out over a year, but you would almost certainly get cancer or have bone marrow damage. The upper limit dose is 5,000mrem or 5Rem per year.
People in America do not get 620 REM. That is ridiculous. The average American gets approximately 300 mrem per year. A single dose of approximately 300-500 REM will kill about 50% of the people within 30 days. The legal limit for Occupational Radiation Workers in the US is 5 REM per year. That would be on top of the approximately 300 mrem a person receives from nature, medical etc...
NO ONE in the US gets 620 REM in a year. That dose is above LD50 (Lethal dose for 50% without medical care)
Avg dose for the US will vary from 300 to 650 or so, depending on the study.
300 mRem to 650 mRem. Forgot the units there.