Answer :

To determine the percentage of nationwide customers who did not return for service after purchasing or leasing a vehicle from a dealer, let’s carefully analyze the options provided.

Given the options:
- 60%
- 30%
- 70%
- 50%

Based on the historical data and accurate information, the correct percentage of customers who did not return for service is 70%.

Therefore, the percentage of nationwide customers who did not return for service after purchasing or leasing a vehicle from a dealer is:
70%.