Indian Cities   With a population of some 1,027 million people, India is now the second country in the world, after China, to cross the one billion mark. The United Nations now estimates that by 2050 India will have overtaken China as the most populous country in the world. Today, Indians make up 16.7 per cent of the world’s population with an annual growth rate of close to two per cent. China's annual population growth is only one per cent, while the world population is growing at an annual rate of 1.4 per cent. In 2001, the sex ratio for the whole of India stood at 933 females to 1,000 males. While this figure constitutes an improvement to the situation in 1991 when there were 927 females per 1,000 males, the figure is still lower than in the 1950s. In countries like the US, Russia and Japan there have been more females than males throughout the 20th century, while in Bangladesh, China and Pakistan the ratio between males and females is moving towards parity. In 2001, India had 35 cities / urban areas with a population of more than one million people. In total, some 108 million Indians, or 10.5 per cent of the national population, live in the country’s 35 largest cities. Mumbai (Bombay) with a population of more than 16 million is now the world’s fourth-largest urban area followed by Kolkata (Calcutta) in fifth place. Urban slum areas are home to more than 40 million Indians or 22.6 per cent of India’s urban population. More than 600 Indian towns and cities incorporate slum areas. The largest slum population in cities with a population of more than one million is found in Mumbai (48.9%) and the lowest in Patna (0.25%).