It's the same as why you wouldn't measure your weight in ounces, but neither would you weigh something very light in pounds - you want a convenient number which is easy to interpret. PC is short for parsec and it's a unit of measurement equal to 3,000,000,000,000,000,000 cm!
Take your annual covered earnings (the earnings on which you pay Social Security payroll taxes), multiply it by that year's index factor and you will obtain your indexed wage for each year you have worked. Next, add up all these indexed wages and divide them by 35 to determine your average wage.
Because 401(k) contributions are subject to Social Security tax, they are included in Social Security wages on Form W-2. The form shows your annual wages earned and taxes withheld for the year; you use it to file your tax return with the IRS and applicable state and local agencies.pecifically, if Social Security tax applies, so does Medicare tax. Your 401(k) contributions are subject to Medicare tax of 1.45 percent, as of 2012.