Japan's Radioactivity & Eastern USA?

For curiosity I've been measuring background radiation outdoors in an Eastern state to see if I there was any measurable change this week due to the winds coming from Japan. Today the average counts per minute was one(1) count higher {at 18 cts/m} over the average of each day up until today.

My instrument's millirem/hour {equivalent dose rate} is determined by dividing counts/min by 1000.

Assuming this added one count per minute remains constant as additional background radiation. What is this additional radiation going to add to an Eastern USA resident's yearly millirem total? _______ (a)

Compare this additional annual radiation to that of a single chest X-ray? _________ (b)