"The increasingly global scope of U.S. business has a variety of dimensions. In trade, the overall level of exports plus imports has risen steadily and substantially in recent decades, increasing from 16% of U.S. gross domestic product (GDP) in 1976 to 29% of GDP in 2016. Cross-border investment is growing even more dramatically. In 1976, the ratio of U.S. private assets abroad to GDP was 0.20; by year-end 2016 the ratio was 1.42."
CRS Report for Congress, RL34115
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html