user: Question: period between 1985 - 1990 have minimum infant mortality rate of what.
Columns: ['Period', 'Births', 'Deaths', 'Difference', 'Crude Birth Rate', 'Crude Death Rate', 'Natural Increase', 'Total Fertility Rate', 'Infant Mortality Rate']
Types: ['text', 'text', 'text', 'text', 'real', 'real', 'real', 'real', 'real']
Sample row: ['1950 - 1955', '230 000', '114 000', '116 000', 238.0, 118.0, 120.0, 270.0, 905.0]
SQL:

assistant: SELECT MIN("Infant Mortality Rate") FROM "Table" WHERE "Period" = '1985 - 1990';