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_20683381_3 (against___percentage_ VARCHAR, ±_yes_side_2008___percentage_ VARCHAR)
### Question:
When +18.1 is the ± yes side 2008 percentage what is the percentage of against?
### Answer:
SELECT against___percentage_ FROM table_20683381_3 WHERE ±_yes_side_2008___percentage_ = "+18.1"