user: Question: How many imr* have tfr* of 4.31?
Columns: ['Period', 'Live births per year', 'Deaths per year', 'Natural change per year', 'CBR*', 'CDR*', 'NC*', 'TFR*', 'IMR*', 'Life expectancy total', 'Life expectancy males', 'Life expectancy females']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'real', 'text', 'text', 'text']
Sample row: ['1950-1955', '70 000', '14 000', '56 000', '44.3', '8.9', '35.4', '6.50', 73.0, '62.6', '60.5', '64.6']
SQL:

assistant: SELECT COUNT("IMR*") FROM "Table" WHERE "TFR*" = '4.31';