To determine the percentage of all Americans who are younger than 65 years old, you would typically look for data indicating the proportion of the population that falls into that age category. Since I can't view images, I'll help you interpret the commonly presented statistics.
Generally, if you have options like 18%, 65%, 83%, and 17%, and you’re looking for those under 65, it’s likely that the higher percentage would represent those younger than 65.
The typical answer in demographic statistics often shows that a significant majority of the population is under 65. Therefore, the most likely answer from the choices provided would be 83%.