Analysis of information sources in references of the Wikipedia article "Fingering (sexual act)" in English language version.
Most women report the inability to achieve orgasm with vaginal intercourse and require direct clitoral stimulation ... About 20% have coital climaxes...
Women rated clitoral stimulation as at least somewhat more important than vaginal stimulation in achieving orgasm; only about 20% indicated that they did not require additional clitoral stimulation during intercourse.
Most women report the inability to achieve orgasm with vaginal intercourse and require direct clitoral stimulation ... About 20% have coital climaxes...
Women rated clitoral stimulation as at least somewhat more important than vaginal stimulation in achieving orgasm; only about 20% indicated that they did not require additional clitoral stimulation during intercourse.