The concentration of impurities in a semiconducter in the production of microprocessors for computer is a normally distributed random variable with mean 127 parts per million and standard deviation 22 parts per million. A semiconducter is acceptable only if its concentration of impurities is below 150 parts per million.

What is the proportion of semiconducters that are acceptable for use?(the area under normal curve for the value of $Z=1.5$ is $0.668$).