CREATE TABLE table_2278 ("Constituency" TEXT, "Electorate" FLOAT, "s Spoilt vote" FLOAT, "Total poll  ( % ) " TEXT, "For  ( % ) " TEXT, "Against  ( % ) " TEXT, "\\u00b1 Yes side 2008  ( % ) " TEXT)

When +18.1 is the yes side 2008 percentage what is the percentage of against?
SELECT "Against (%)" FROM table_2278 WHERE "\u00b1 Yes side 2008 (%)" = '+18.1'
SELECT "Against (%)" FROM "table_2278" WHERE "\u00b1 Yes side 2008 (%)" = '+18.1'