Age Frequency of mammograms Total Total Total 100.00 Total At least once a year 27.27 Total Every two years 41.75 Total Every three years or more 8.84 Total Never 22.14 20 to 24 years old Total . 20 to 24 years old At least once a year . 20 to 24 years old Every two years . 20 to 24 years old Every three years or more . 20 to 24 years old Never . 25 to 34 years old Total 100.00 25 to 34 years old At least once a year 14.45 25 to 34 years old Every two years 10.49 25 to 34 years old Every three years or more 6.89 25 to 34 years old Never 68.16 35 to 44 years old Total 100.00 35 to 44 years old At least once a year 24.78 35 to 44 years old Every two years 20.57 35 to 44 years old Every three years or more 10.47 35 to 44 years old Never 44.19 45 to 54 years old Total 100.00 45 to 54 years old At least once a year 32.67 45 to 54 years old Every two years 42.90 45 to 54 years old Every three years or more 8.46 45 to 54 years old Never 15.96 55 to 64 years old Total 100.00 55 to 64 years old At least once a year 28.46 55 to 64 years old Every two years 62.92 55 to 64 years old Every three years or more 5.38 55 to 64 years old Never 3.24 65 to 74 years old Total 100.00 65 to 74 years old At least once a year 27.61 65 to 74 years old Every two years 49.37 65 to 74 years old Every three years or more 9.84 65 to 74 years old Never 13.19 75 years old and over Total 100.00 75 years old and over At least once a year 19.19 75 years old and over Every two years 24.16 75 years old and over Every three years or more 17.46 75 years old and over Never 39.19