Refer to the passage below and then answer the question afterwards in the same language as the passage:

Passage: In 1978, the State Bank of Vietnam (Ngân hàng Nhà nước Việt Nam) introduced notes in denominations of 5 hào, 1, 5, 10, 20, and 50 đồng dated 1976. In 1980, 2 and 10 đồng notes were added, followed by 30 and 100 đồng notes in 1981. These notes were discontinued in 1985 as they gradually lost value due to inflation and economic instability.

Question: When did the State Bank of Vietnam added 2 and 10 dong notes?
In 1980