National census results in the past few decades have been disputed. The results of the most recent census were released in December 2006 and gave a population of 140,003,542. The only breakdown available was by gender: males numbered 71,709,859, females numbered 68,293,008. According to the United Nations, Nigeria has been undergoing explosive population growth and has one of the highest growth and fertility rates in the world. By their projections, Nigeria is one of eight countries expected to account collectively for half of the world's total population increase in 2005–2050. The UN estimates that by 2100 the Nigerian population will be between 505 million and 1.03 billion people (middle estimate: 730 million). In 1950, Nigeria had only 33 million people. In 2012, President Goodluck Jonathan said Nigerians should limit their number of children.