Boston was transformed from a relatively small and economically stagnant town in 1780 to a bustling seaport and cosmopolitan center with a large and highly mobile population by 1800. It had become one of the world's wealthiest international trading ports, exporting products like rum, fish, salt and tobacco. The upheaval of the American Revolution, and the British naval blockade that shut down its economy, had caused a majority of the population to flee the city. From a base of 10,000 in 1780, the population approached 25,000 by 1800. The abolition of slavery in the state in 1783 gave blacks greater physical mobility, but their social mobility was slow.