Amswer: 2006

Save for a lighting black out during World War II, the Times Square New Year’s Eve ball has dropped every year since 1907. The earliest balls were simple constructions of wood and incandescent lights, small enough to be hoisted aloft and lowered by a few men pulling on a pulley-assisted rope. By the 1950s the ball had grown in size, was constructed out of aluminum, and adorned with even more lights. Still, from the 1907 to the the 1990s, the process remained largely unchanged.

In 1996 the ball dropped for the first time by a computer controlled lighting system, paving the way for the biggest change in the Times Square ball–the 2006 upgrade to LED lighting. Thanks to the LED system the ball is capable of displaying millions of colors and patterns, a far cry from the simple incandescent system used throughout the last century.

Bonus Trivia: While we now use time balls to celebrate the New Year, they were originally used as a tool to help ships synchronize their on-board clocks while out at harbor.