Many Irish people have left Ireland and moved to the United States, Canada, Australia, and South America. The Great Famine in the 1840s forced many to leave; it is estimated almost a million people died of starvation, and a million more emigrated. From a maximum of over 8 million in 1841, the total Irish population dropped to just over 4 million in the 1940s. Since then, the population has grown to over 6 million. This has been helped by the economic growth of the "Celtic Tiger" and since 2004 immigration from countries in Eastern Europe such as Poland.