 Since many radio stations in the US adopt a format change to Christmas music each December, many holiday hits have an annual spike in popularity during the last few weeks of the year and are retired once the season is over.In December 2011, "Billboard" began a Holiday Songs chart with 50 positions that monitors the last five weeks of each year to "rank the top holiday hits of all eras using the same methodology as the Hot 100, blending streaming, airplay, and sales data", and in 2013 the number of positions on the chart was doubled, resulting in the Holiday 100.Many Crosby recordings have made appearances on the Holiday 100 and are noted below according to the holiday season in which they charted there.