The European Union\'s poorest country Bulgaria will face the world\'s sharpest decline in working-age population in the coming decades, creating major economic challenges, the World Bank warned on Friday. \"Bulgaria is heading for the steepest drop in the working-age population of any country,\" the institution said in a new report presented in Sofia on Friday. \"By 2050, one in three Bulgarians is projected to be older than 65 and only one in two Bulgarians will be of working age.\" Bulgaria\'s population has dropped from almost nine million at the fall of communism in 1989 to 7.3 million in 2011. Almost half of people are below the poverty line and live at risk of social exclusion -- the worst ratio across the 28-nation EU. The decline in the labour supply in the next four decades will push income levels down, depress economic growth and send public debt soaring as pension and health care costs shoot up, the World Bank said. It urged swift reforms of the pension and medical systems and to improve the provision of care for the elderly, as well as policies to boost productivity, create jobs and encourage emigrants to return. Earlier this year nationwide protests against poverty and corruption saw several people set themselves on fire and prompted the government to resign in February. The new administration of technocrat Prime Minister Plamen Oresharski, which has also faced major protests, has pledged to kickstart the economy and tackle rising poverty.