As the workforce grows, the share occupied by older workers is growing as well. The Bureau of Labor Statistics (BLS) projects that 25% of the labor force in 2024 will be 55 or older. That’s up from 22% in 2014 and just 12% in 1994.

Aging baby-boomers are fueling this increase as those born between 1946 and 1964 will have reached ages 60 to 78. Many are expected to continue working, even after qualifying for Social Security benefits.

Why are people staying in the workforce longer? They are healthier and have a longer life expectancy than previous generations. They are better educated, increasing the chances of staying on the job.

Despite these positive signs, older workers are most at risk of seeing their jobs disappear at the hands of technology.

Thirteen percent of workers 55 or older are in occupations that the BLS projects will shrink by 2024, compared with 9% of workers under 35.

And for older workers who lose their jobs, transitioning to a new career is harder. While sometimes difficult, older workers are being forced to invest in new skills and re-think their career choices. That means exploring alternative work models or the gig economy. Consulting, freelancing and on-call jobs have increased more than for younger workers. As of late 2015, 24% of employed 55- to 75-year-olds were in alternative work arrangements, compared with just 14% of prime-age (25- to 54-year-old) workers.