Pick one calendar rule and see its history against holding the same symbol for the same number of sessions, year by year, through the research cutoff. The figures come from the same evaluator as the Scan. Returns are gross: your round-trip cost is yours to apply.
Every year, from the first session of the week to the first session of the next. Week 1 starts on January 1 and each week is seven days, dated in a year without February 29; week 52 exits in the next year’s first week.