Complex sentence: However, the song has been released during every decade since 1973, and has been covered by numerous artists, ensuring it remains popular; this was reflected in a 2007 poll when "Merry Xmas Everybody" was voted the UK's most popular Christmas song.
Split into simpler sentences: However, the song has been released during every decade since 1973, and has been covered by numerous artists, ensuring it remains popular. In a 2007 poll, "Merry Xmas Everybody" was voted the UK's most popular Christmas song.