user: Question: What is the lowest Natural Change, when Natural Change (Per 1000) is 19.1, and when Crude Birth Rate (Per 1000) is less than 28.3?
Columns: ['Average population (x 1000)', 'Live births', 'Deaths', 'Natural change', 'Crude birth rate (per 1000)', 'Crude death rate (per 1000)', 'Natural change (per 1000)']
Types: ['real', 'real', 'real', 'real', 'real', 'real', 'real']
Sample row: [233.0, 6559.0, 1938.0, 4621.0, 28.2, 8.3, 19.8]
SQL:

assistant: SELECT MIN("Natural change") FROM "Table" WHERE "Natural change (per 1000)" = 19.1 AND "Crude birth rate (per 1000)" < 28.3;