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.
To correct your Social Security earnings record, contact us at 1-800-772-1213 (TTY 1-800-325-0778). It will be helpful to have information such as Forms W-2, pay stubs, etc.