The continuum of controlling an assistive robotic manipulator (ARM) ranges from manual control to full autonomy. Shared control of an ARM operates in the space between manual control and full autonomy. This paper reviews the status quo on shared control of ARMs. Though users and ARMs can divide responsibilities for a manipulation task in different ways, most research in this area focus on maximizing robot autonomy and minimizing user control, while other work split the responsibilities more evenly between the ARM and the user. User studies in this area are very limited. More research is needed to investigate the overall performance, workload, and satisfaction across different levels of autonomy for the shared control of ARMs.