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.
Enter/review the employer information for this wage report. If you are filing for your own company's employees, the information on the file with Social Security will be shown on this screen. The fields on this page correspond to boxes on the paper Form W-2 and Form W-3 and should be completed the same way. Contact the Internal Revenue Service if you need assistance with providing this information. Verify the contact information for this submission. Provide other information such as Establishment Number and Employer State ID Number if applicable.