Privately held companies use ESOPs most for business transtion, and the vast majority of ESOPs are in this category. The number of comapnies doing this has risen slightly per year but the numbe rof participants has grown a lot. You can see data on this at https://www.nceo.org/articles/employee-ownership-by-the-numbers
Many public companies make their shares available as an investment option and/or match employee deferrals with company stock. In the wake of Enron, WorldCom, Lucent and many other companies that saw severe drops in their stock in the early 2000s, and then again in recession of 2008 and 2009, this practice became markedly less common, with employee investment in company stock in 401(k) plans dropping from a peak of about 19% of all assets to under 10% today. The "stock-drop" companies faced numerous lawsuits, and while few have actually been decided in favor of the plaintiffs, there have been a number of settlements for tens of millions of dollars each. In the Pension Protection Act of 2006, Congress also made changes to these plans to allow employees to diversify out of company stock quickly.
