Final answer:
The prevalence of Alzheimer's disease is higher in individuals over the age of 85 compared to younger age groups.
Step-by-step explanation:
The prevalence of Alzheimer's disease in individuals over the age of 85 is significantly higher compared to younger age groups. According to the provided table, in the 61-70 age group, the prevalence is 21%, and it remains relatively constant in the 51-60 and 71-80 age groups. However, there is a steep increase in the prevalence of Alzheimer's in the >80 age group, which includes individuals over 85 years old.