Coca-Cola (KO) shareholders easily re-elected Warren Buffett to its board, although the billionaire investor did receive a notable amount of votes against him.Buffett, who is Coke's largest shareholder, received 84% of the vote, according to the Atlanta Journal-Constitution, but it was the first time in recent memory that a double-digit percentage of shareholder votes were withheld from a sitting director. Each of the other 15 directors received at least 96% of the votes cast, according to the paper. Buffett had come under fire in recent months from certain shareholders who contended he was not a truly independent director. Investment advisory group Institutional Shareholder Services said last month that Buffett shouldn't be re-elected to the board because companies controlled by his Berkshire Hathaway ( BRKA) holding company, McLane and Dairy Queen, do business with Coca-Cola. The proxy group, whose opinions on corporate governance often hold sway with institutional investors, thought Berkshire's ownership of the companies created a conflict of interest for Buffett and could influence his independence with Coke. Earlier this month, CalPERS, the California Public Employees' Retirement System, said it was withholding its votes for Buffett and eight other Coca-Cola board members because of their lack of independence.