Final answer:
The percentage of teens not wearing seat belts in fatal crashes can vary, but based on available statistics, about 57% of teen driver involved in fatal crashes were not wearing seat belts in 2017.
Step-by-step explanation:
The question asks for the percentage of teens who are not wearing seatbelts in a fatal crash. Unfortunately, the provided information does not directly answer this question. However, we can make an estimate based on available statistics. According to the National Highway Traffic Safety Administration (NHTSA), in 2017, out of the total number of teen passenger vehicle drivers involved in fatal crashes, about 57% were not wearing seat belts. This statistic gives us an idea of the percentage of teens not wearing seat belts in fatal crashes, although the specific percentage may vary from year to year. So, it can be inferred that a significant percentage of teens involved in fatal crashes were not wearing seat belts.