Teacher:Generate a correct and concise answer for the question based on the words in the context.
Teacher: Now, understand the problem? Solve this instance: Context : The ZBD-97, or Type 97, has been in service with the PLA ground forces since 2006, in the armored units of the Guangzhou and Nanjing military regions.
Question : What year was the service entry date for ZBD-97?
Student:
2006