Planning to retire at 65? Most Americans stop working years earlier — and not because they want to.

The typical American retires far earlier than he or she expects to, and it's often not by choice, according to new research from the Transamerica Center for Retirement Studies. 

The median retirement age in the U.S. is 62, with nearly six in 10 retirees telling the research firm that they stepped back from the workforce earlier than they had planned. Almost half of those people said the reason came down to health issues, such as physical limitations or disability. Losing a job or an organizational change at their employer were among the other reasons people stopped working before they planned to retire.