July 11 (Reuters) - Amazon.com Inc said on Tuesday it has sold more than three times as many Echo family devices worldwide partway through its Prime Day sale than for the entire event in 2016, an early sign of its performance on one of its biggest business days of the year.

Amazon is selling the voice-controlled Echo speaker at half price, or $89.99, for members of its Prime shopping club, with other discounts for related devices. Getting more speakers into homes is a top initiative at Amazon, which wants to encourage shopping by voice command and gather more user data to improve Echo’s voice technology.