Preventative practices Frequency of mammograms, by nationality. Females aged 20 years old and over who have had mammogram at some point in time Units: percentages ;Total;At least once a year;Every two years;Every three years or more;Never; Total;100.00;27.27;41.75;8.84;22.14; Spanish;100.00;27.24;43.17;8.72;20.86; Foreign;100.00;28.38;23.27;9.95;38.40; No data recorded;100.00;0.00;64.68;22.33;13.00; Notes: The symbol '.' shall be deemed as data which cannot be provided since it may be affected by sampling errors. The symbol '..' shall be deemed as data which is not collected. The symbol '...' shall be deemed as an 'error of division by zero'. Source: Ministry of Health and Consumption and INE