Not only are there significnatly more Americans over the age of 65 in the workforce today, compared with 30 years ago, a December 2017 study by SeniorLiving.org says that their numbers are growing rapidly, increasing nearly 35 percent just between 2011 and 2016.

According to a report from the Society for Human Resource Management, the senior segment is projected by the Bureau of Labor Statistics to be the fastest-growing group in the workforce through 2024. While in 2011, 6.6 million Americans age 65 or older were working in the U.S., by 2016 that number had risen to 8.9 million people—an increase of nearly 35 percent.

Whatever happened to retirement? In a word, money. In another, longevity. "Several factors influence how long people stay in the labor force," Jen Schramm, SHRM-SCP, senior strategic policy advisor for labor market issues at the AARP Public Policy Institute, is quoted saying in the report.