Final answer:
No precise answer can be provided based on the available information, but since about one-third of recent high school graduates primarily participate in the workforce, it is possible that a significant proportion of high school students, potentially near 50% or more, work in after-school jobs before graduating.
Step-by-step explanation:
The question asks about the percentage of today's high school students who will have worked in an after-school job before graduating. While none of the provided reference information gives a specific answer to this question, the closest related fact tells us that about one-third of recent high school graduates primarily participate in the workforce. This includes those who are employed or are looking for employment. If we extrapolate from this data, we might infer that a significant proportion of high school students likely work after-school jobs as well, potentially approaching or exceeding the 50% mark.
Please note that the reference information provided does not directly give the exact percentage, and for a precise answer, one would need to refer to specific labor statistics or a dedicated survey result on high school student employment.