user: Question: What source of wealth has a value of £5726m?
Columns: ['Rank', 'Value', 'Name', 'Source of wealth', '2007 Rank']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1.0, '£27700m', 'Lakshmi Mittal', 'Steel', '1']
SQL:

assistant: SELECT "Source of wealth" FROM "Table" WHERE "Value" = '£5726m';