Last year, Crab Shack had sales of $200,000, total expenses of $120,000, and corporate taxes of $30,000. Its total assets are $200,000 and its total liabilities are $100,000. The company followed its usual practice of repurchasing shares from shareholders as a fixed percentage of its net income, amounting to a cash outflow of $10,000 for last year. What is Crab Shack's internal growth rate?