According to Sony, they introduced the 3.5 inch floppy disk size to the world in 1981, and began sales within Japan in 1983. Sony had shipped approximately 47 million disks within the country at its peak around the year 2000, but that number had fallen to around 8.5 million by 2009.
Sony announced on April 23rd that they will be discontinuing sales of the classic 3.5 inch floppy disk in Japan in 2011. The news marks a major end to a nearly three decade history of the disk type that the company helped to pioneer.
Sony 3.5 inch floppy 1981-2011