NRF | 4-5-4 Calendar - National Retail Federation | Home When and Why Was The 4-5-4 Calendar created?What Is The Purpose of The 4-5-4 Calendar?What Is A 53-Week Year?How Does NRF Determine The Need For A 53rd Week?How Are Sales During A 53-Week Year Compared to The Subsequent Year?The 4-5-4 Calendar, which is widely followed by retailers today, was derived in the 1930s during an informal inter-industry discussion. Prior to and during the 1930s, retailers used a straight calendar to report monthly sales. This calendar became problematic as Saturdays and Sundays became an increasingly large percentage of sales, since the number of weekends in a month varied year to year. A calendar that maintained the same number of weekends in comparable months was desired and the 4-See more on nrf Calendar 2014 - timeanddate United States 2014 – Calendar with American holidays. Yearly calendar showing months for the year 2014. Calendars – online and print friendly – for any year and month. Menu timeanddate.