Staphylococcus aureus (. ) is a bacterium that commonly colonises human skin and mucosa without causing any problems. It can also cause disease, particularly if there is an opportunity for the bacteria to enter the body, for example through broken skin or a medical procedure.
Structure of Social Security Numbers. A Social Security Number (SSN) consists of nine digits, commonly written as three fields separated by hyphens: AAA-GG-SSSS. The first three-digit field is called the area number. The central, two-digit field is called the group number. The final, four-digit field is called the serial number.
Since 1973, social security numbers have been issued by our central office. The first three (3) digits of a person's social security number are determined by the ZIP Code of the mailing address shown on the application for a social security number. Prior to 1973, social security numbers were assigned by our field offices.