The invention of the transistor in the 1950s, a key active component in practically all modern electronics, led to many technological developments and a significant expansion of the U.S. technology industry. This, in turn, led to the establishment of many new technology companies and regions around the country such as Silicon Valley in California. Advancements by American microprocessor companies such as Advanced Micro Devices (AMD) and Intel, along with both computer software and hardware companies such as Adobe Systems, Apple Inc., IBM, Microsoft, and Sun Microsystems, created and popularized the personal computer. The ARPANET was developed in the 1960s to meet Defense Department requirements, and became the first of a series of networks which evolved into the Internet. The United States was ranked third (after Switzerland and Sweden) in the Global Innovation Index in 2019 and 2020.