The end of World War II brought a baby boom to many countries, especially Western ones. There is some disagreement as to the precise beginning and ending dates of the post-war baby boom, but it is most often agreed to begin in the years immediately after the war, ending more than a decade later; birth rates in the United States started to decline after 1957. In countries that had suffered heavy war damage, displacement of people and post-war economic hardship, such as Germany and neighboring Poland, the boom began some years later.