Please answer a question about the following article about Boston:

Boston's colleges and universities have a significant effect on the regional economy. Boston attracts more than 350,000 college students from around the world, who contribute more than $4.8 billion annually to the city's economy. The area's schools are major employers and attract industries to the city and surrounding region. The city is home to a number of technology companies and is a hub for biotechnology, with the Milken Institute rating Boston as the top life sciences cluster in the country. Boston receives the highest absolute amount of annual funding from the National Institutes of Health of all cities in the United States.

Students from around the world contribute how much a year to Bostons economy?
$4.8 billion