What is the most popular shipping company in the USA?

Could you tell me which shipping company currently holds the title of being the most popular in the United States? I'm curious to know which provider stands out among the many options available, in terms of both customer satisfaction and market share. Is there a particular reason behind its popularity, perhaps related to its services, reliability, or pricing? Understanding the factors that contribute to its success would be invaluable information for those seeking the best shipping solution for their needs.