According to a national health survey, the serum cholesterol levels of men aged 18 to 24 are normally distributed with a mean and standard deviation (in mg/100mL) of 178.1 and 40.7, respectively. One criterion for identifying risk of coronary disease is a cholesterol level above 300. If a man aged 18-24 is randomly selected, find the probability that his serum cholesterol level is above 300. Does this probability warrant serious concern?