Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_15 (year INTEGER, issue_price VARCHAR, mintage VARCHAR)
### Question:
What is the Year of the Coin with an Issue Price of $1089.95 and Mintage less than 900?
### Answer:
SELECT SUM(year) FROM table_name_15 WHERE issue_price = "$1089.95" AND mintage < 900