Value added by manufacture surpassed $8.6 billion in 1982, more than double the total for 1977. In 1949, about 55,200 Puerto Rican workers were employed in industrial jobs, 26% of them in sugar refining. By 1992, despite the loss of many jobs in the sugar industry, the number was 158,181 with a total payroll of $2.7 billion. The leading employment categories in 1992 were apparel and textiles, 30,700; chemicals and allied products, 25,400; food and kindred products, 21,000; electric and electronic equipment, 18,400; and instruments, 15,900. The growth areas were electric and electronic equipment, up 47% from 1977, and instruments and related products, up 60%.
According to the 1992 Census of Manufactures, the value of shipments amounted to $31 million, of which chemicals and allied products accounted for $13.3 billion; food and kindred products, $5.2 billion; and electronic and electric equipment, $2.8 billion.
There were more than 90 pharmaceutical plants representing 20 of the world's leading drug and health companies. The largest included Johnson & Johnson (Rio Piedras), Abbott Chemicals (Barceloneta), Bristol-Myers Squibb (Humacao), Warner-Lambert (Vega Baja), and Schering-Plough (Manati). In 1991, Baxter International (medical devices) was one of the commonwealth's largest non–locally based manufacturers, with 10 plants; Westinghouse Electric (electric components) had 15; Sara Lee (men's underwear), 6; and Motorola (radio equipment), 4.
In addition to the production of pharmaceuticals, electrical and electronic products, and textiles, other industries include: bottling, chemicals, clay and glass, distilling, leather, metal (including precision instruments), printing, publishing, and software manufacturing.
Industries tend to be labor intensive. The construction industry has been a growth area in recent years; in 1997, construction growth was estimated at around 15%. By 2003, however, the construction sector saw a downward trend. Manufacturing in 2003 accounted for 40% of GDP, more than double the percentage share of the US mainland. In 2002, employment in manufacturing declined by 8.5%, compared with a decline of 6.9% on the mainland.
Puerto Rico has two foreign free-trade zones, in Mayagüez and San Juan. In January 1987, the Puerto Rico Industrial Incentives Act was passed to make more manufacturing and export service industries eligible for tax exemptions.