If that makes it look like the gap is narrowing, keep in mind that only a year before summer films out-earned their winter counterparts $4.3 billion to $2.1 billion. The summer box office can double up on its smaller winter sibling almost at will. However, as Beverly Hills Cop proved, winter blockbusters can still win out for best box-office draw overall. Since 1984, 10 holiday-released films -- Beverly Hills Cop, Rain Man, Home Alone, Aladdin, Toy Story, Titanic, The Grinch, Harry Potter and the Sorcerer's Stone, Lord of the Rings: Return Of The King and Avatar -- went on to become the biggest films of the year. Two of them -- Titanic at $659 million and Avatar at $760.5 million -- rank as the top-grossing U.S. films of all time. Even adjusted for inflation, Titanic still cracks the Top 5 with a $1.1 billion take. While one great winter film may not be enough to declare a new blockbuster season, it does help balance the movie mix a bit. Since 2000, the industry's box office revenue has risen every time a winter movie has been the top earner. In fact, only The Grinch in 2000 failed to help increase movie ticket sales from one year to the next. The first Harry Potter installment in 2001 helped boost ticket sales 4.7% from the year before, while Avatar fueled a 5.3% jump in ticket sales in 2009 -- which was the last time Hollywood got U.S. moviegoers to buy more than 1.4 billion tickets to its films. Get enough kids out of school and enough discretionary vacation cash floating around, and just about any season can become a blockbuster season for the movie industry. Hollywood's been capitalizing on that lucrative wintry mix for a while now, and its strategy is about as new as an '80s buddy cop film or Glenn Frey's The Heat Is On.-- Written by Jason Notte in Portland, Ore.Follow @notteham >To contact the writer of this article, click here: Jason Notte. >To submit a news tip, send an email to: firstname.lastname@example.org.