The rates of the 1st exposure, the 2nd exposure and the 3rd exposure are 70.48%, 21.77% and 7.75%, respectively.
Tỷ lệ phơi nhiễm 1 lần: 70,48%, phơi nhiễm 2 lần: 21,77%, phơi nhiễm 3 lần trở lên: 7,75%.