Preventative practices Frequency of mammograms, by age group. 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 20 to 24 years old . . . . . 25 to 34 years old 100.00 14.45 10.49 6.89 68.16 35 to 44 years old 100.00 24.78 20.57 10.47 44.19 45 to 54 years old 100.00 32.67 42.90 8.46 15.96 55 to 64 years old 100.00 28.46 62.92 5.38 3.24 65 to 74 years old 100.00 27.61 49.37 9.84 13.19 75 years old and over 100.00 19.19 24.16 17.46 39.19 Notes: .Data protected by statistical secrecy 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