After its founding in 1630, Boston's economy was initially based on shipping and shipbuilding, which retained their central position until the nineteenth century when they were eclipsed by manufacturing, which was fueled by technological advances, the development of railroads, and a steady supply of immigrant labor. Boston's traditional industries started to decline in the twentieth century, especially during the Great Depression of the 1930s. However, there was an upsurge in industrial demand during World War II.
Since then new industries have helped keep Boston's economy strong, as well as spur growth in the service sector. The area circling the city along Route 128 has seen a proliferation of new research-based firms, becoming one of the nation's leading high-technology centers, with the nation's second-highest number of biotechnology firms. Boston has also grown into one of the country's leading banking, insurance, and investment centers. The largest employment sectors are service industries (especially health care), government (Boston's local government had a work force of 22,000 in 1995), and the financial sector. In 1996 Boston's labor force numbered 288,267, and unemployment stood at four-anda-half percent.
The Boston area is considered a leading manufacturing center, especially in electronics and computers. Other manufacturing industries in the region include machinery, motor vehicles and other transport equipment, ships, apparel, cameras, printing and publishing, chemicals, shoes, books, and textiles. Since the 1980s Boston has become known for its research-based high-tech industries, although these are largely located outside city limits along Route 128, which circles the city. Major companies headquartered in the Boston area include Raytheon, Gillette, Fidelity Investments, and Digital Equipment Corporation.