Mr. Barrett is the first executive committee member to resign from the company since 1993, when a group of top traders quit.
That impatience has been evident across Latin America, where eight presidents have been ousted or forced to resign in popular uprisings since 2000.
His health problems had become so troubling that he had been asking repeatedly to resign since early 1876.
He is the sixth Cabinet member to resign since the re-election of President Bush.
Bannon was the seventh state premier to resign in disgrace since 1982.
Four ministers have been forced to resign since November amid questions of nepotism and ethical lapses.
He had been under pressure to resign since the report's release.
Walter may have resigned willingly, as he had talked of resigning his secular duties since 1194.
She was the first Minister to resign voluntarily since 2003.
Kine Karlsen resigned as President in late October 2010, after a leave of absence since August 2010.