In relation to the above article I posted about Japan's declining population and Tokyo's shrinking suburbs, I figured I'd see what countries have shrunk the most, so here they are:
Country....peak population (year)...population 2016...% decline
Georgia........5,466,610 (1989)........3,979,781.........-27.2%
Latvia..........2,665,710 (1989)........1,955,742.........-26.6%
Lithuania......3,699,352 (1991)........2,850,029.........-23.0%
Bulgaria.......8,960,387 (1985)........7,097,796.........-20.8%
Romania.......23,489,360 (1990)......19,372,733........-17.5%
Estonia.........1,570,050 (1989)........1,309,104.........-16.6%
Bosnia..........4,559,256 (1989)........3,802,134.........-16.6%
Armenia.......3,544,694 (1990)........3,026,047.........-14.6%
Ukraine........51,370,009 (1990).......44,624,372.......-13.1%
Croatia.........4,780,626 (1989)........4,225,001.........-11.6%
Albania.........3,281,453 (1990)........2,903,700.........-11.5%
Serbia..........9,884,146 (1995).........8,812,705........-10.8%
Hungary........10,759,021 (1980).......9,821,318........-8.7%
Belarus.........10,241,136 (1991).......9,481,521........-7.4%
Moldova........4,375,312 (1992).........4,062,861........-7.1%
Russia..........148,435,811 (1993)......143,439,832.....-3.4%
Portugal........10,590,259 (2009).......10,304,434.......-2.7%
Greece..........11,179,425 (2009)......10,919,458........-2.3%
Germany.......82,010,184 (1998).......80,682,351.......-1.6%
Spain............46,708,365 (2011).......46,064,604.......-1.4%
Japan...........127,340,884 (2009)......126,323,715......-0.8%
Poland..........38,619,973 (2014)........38,593,160.......-0.1%
Cuba............11,392,888 (2016)........11,392,888.......0.0%
Italy.............59,801,003 (2016)........59,801,003.......0.0%
Those countries that have currently declined by over 10% could be half their peak population by 2100, while the other countries on this list could lose up to a quarter or a third of their population by 2100.
There are many other countries projected to shrink over the course of the next few decades, but because that is purely speculation they are not included. Also, only sovereign states are included, Puerto Rico, the US Virgin Islands and Martinique have also shrunk.