'Work activity during the reference year' refers to whether or not a person 15 years or over worked during the reference year. For those who did work, this refers to the number of weeks in which the person worked for pay or in self-employment during the reference year at all jobs held, even if only for a few hours, and whether these weeks were mostly full time (30 hours or more per week) or mostly part time (less than 30 hours per week).