To succeed in the U.S. economy, companies must constantly adapt to changing conditions. Though some of the nation’s largest corporations — companies such as General Electric, Exxon Mobil, and Walmart — have always dominated, for many American consumers the landscape of companies has shifted over the course of their lifetimes.

To identify the largest companies in the year you were born, 24/7 Wall St. reviewed annual revenue figures for companies on the Fortune 500 each year from 1955 through 2018. General Motors was the nation’s largest company throughout the 1950s, ‘60s, and part of the ‘70s. Exxon Mobil edged out the automaker in 1975, but GM returned to the No. 1 position periodically in subsequent years.

Since 2001, either Walmart or Exxon Mobil has occupied the top spot. With revenue of over $500 billion in its most recent fiscal year, the global retailing giant is the world’s largest company by revenue, and the largest employer in 22 states.

Though industrial companies used to be among the largest in terms of revenue, internet and tech giants like Google, Apple, and Amazon, are decisively making their way toward the top of the list.

These large companies tend to pay their executives well, and have some of the highest paid CEOs in the country. Some of the CEOs of these companies make over 1,000 times more than their employees.

Click here to see the biggest company the year you were born