user: Question: When sigma (with 1.5σ shift) is 2.5, what percent is defective?
Columns: ['Sigma level', 'Sigma (with 1.5σ shift)', 'DPMO', 'Percent defective', 'Percentage yield', 'Short-term C pk', 'Long-term C pk']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, '-0.5', '691,462', '69%', '31%', '0.33', '–0.17']
SQL:

assistant: SELECT "Percent defective" FROM "Table" WHERE "Sigma (with 1.5σ shift)" = '2.5';