The caregiver support ratio refers to the the number of potential caregivers in the 45 to 64 age range who can take care of people 80 plus years old. As the chart below shows, that ratio peaked in 2010 but will start going down rapidly after that.
The implications for baby boomers are clear - if you don't have a large number of potential family caregivers, you better have the means to pay for future caregivers.