"Japan's population, which peaked at 128 million in 2004, is falling. If current trends continue, it will drop below 90 million within 50 years and fall by two-thirds to 40 million within 100 years ."
Source: The Future of Japan’s Immigration Policy: a battle diaryBy Sakanaka HidenoriIntroduction by Andrew Taylor and David McNeill
Translation by Andrew J. I. Taylor
http://www.japanfocus.org/-Sakanaka-Hidenori/2396