Passage: On his 50th birthday, in 1906, Tesla demonstrated a 200 horsepower (150 kilowatts) 16,000 rpm bladeless turbine. During 1910–1911, at the Waterside Power Station in New York, several of his bladeless turbine engines were tested at 100–5,000 hp. Tesla worked with several companies including from 1919–1922 in Milwaukee, for Allis-Chalmers. He spent most of his time trying to perfect the Tesla turbine with Hans Dahlstrand, the head engineer at the company, but engineering difficulties meant it was never made into a practical device. Tesla did license the idea to a precision instrument company and it found use in the form of luxury car speedometers and other instruments.

Question: What year did the 50th birthday fall on?
1906