How Much? It’s Political, Now.
It probably began with the 50 or so statewide unions barring anyone who didn’t pass the state exam from pronouncing accounting opinions. It hit high gear when FDR’s Congress (and it WAS FDR’s Congress) established the Securities and Exchange Commission and put crooked Joseph P. Kennedy in charge of it.
Then came Enron and the establishment of the government’s accounting standards board, supplanting that of the American Institute of Certified (by the state) Public Accountants, known as the Financial Accounting Standards Board (FASB).