You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Plymouth

Context:
Devonport Dockyard is the UK's only naval base that refits nuclear submarines and the Navy estimates that the Dockyard generates about 10% of Plymouth's income. Plymouth has the largest cluster of marine and maritime businesses in the south west with 270 firms operating within the sector. Other substantial employers include the university with almost 3,000 staff, as well as the Tamar Science Park employing 500 people in 50 companies. Several employers have chosen to locate their headquarters in Plymouth, including Hemsley Fraser.

Question:
About what percentage of Plymouth's income comes from the Dockyard?

10%