Age. Kinsey, Pomeroy, and Martin (1949) stated that of the eleven factors that are significant in understanding human sexuality, none seemed more important than age. Sexual behavior in women and men declines steadily from adolescence into older age, and to a lesser extent there is diminution (Taking away; reduction; lessening; incompleteness.The term diminution is used in law to signify that a record submitted by an inferior court to a superior court for review is not complete or not fully certified.)
..... in sexual desire (Maurice, 1999).
Some researchers report that older adults continue to be interested in sex as long as poor health does not affect their sexual desire. In particular, aging does not appear to have any effect on female sexual desire (Masters, Johnson, & Kolodny, 1994).
(Bold mine)