FGM Classification and sexual pleasure
The WHO categorizes FGM in four classes:
- Type 1: separated in Type 1a (removal of clitoral hood/prepuce), and Type 1b (removal of the clitoris)
- Type 2: separated in Type 2a (removal of the labia minora), Type 2b (removal of the clitoris and labia minora), and Type 2c (removal of the clitoris, labia minora and labia majora)
- Type 3: separated in Type 3a (removal and apposition of the labia minora), and Type 3b (removal and apposition of the labia majora). Both can - but do not necessarily do - remove the clitoris.
- Type 4: Other
The clitoris is an important source of sexual pleasure, so its removal obviously reduces sexual pleasure. The apposition of the labia minora or majora can also impact sexual pleasure.
This means that Type 1b, Type 2 a/b, and Type 3a/b will reduce sexual pleasure. Type 1a is more comparable to male circumcision, and Type 4 is a broad category that may or may not impact sexual pleasure.
The 10% mentioned by the OP likely refers to the 10% of women that experienced Type 3:
The type of procedure performed also varies, mainly with ethnicity. Current estimates (from surveys of women older than 15 years old) indicate that around 90% of female genital mutilation cases include either Types I (mainly clitoridectomy), II (excision) or IV (“nicking” without flesh removed), and about 10% (over 8 million women) are Type III (infibulation). Infibulation, which is the most severe form of FGM, is mostly practiced in the north-eastern region of Africa: Djibouti, Eritrea, Ethiopia, Somalia, and Sudan
Clitoridectomy means the (partial) removal of the clitoris, which can be part of Type 1 and 2 as well, and which will reduce sexual pleasure.
General Research on FGM and sexual pleasure
Most research focuses on specific countries, as practices vary greatly. Because of this, it is difficult to give more concrete facts on such a broad question.
Still, here is an article looking at 7 studies:
While three of the seven FGM/C studies that included a control group found decreased orgasmic functioning in affected women, no study fully controlled for demographic differences between groups or separated the FGM/C group by clitoral integrity. The impact of FGM/C on orgasm therefore remains unknown; however, indirect evidence suggests that orgasm rates would be reduced in women who cannot engage in direct stimulation of the external clitoris. Female genital mutilation/cutting and orgasm before and after surgical repair.
Another article also contains an overview of some studies, with more concrete numbers:
There is increasing evidence that FGM damages sexual function and this would seem logical given the removal of sexually sensi- tive tissue such as the clitoris. However studies on sexual function post-FGM are small and often lack appropriate standardised sexual function questionnaires and appropriate control groups. Alsibiani and Rouzi recruited 130 sexually active women with FGM and 130 sexually active women without FGM in Jeddah, Saudi Arabia. Each participant completed a version of the Female Sexual Function Index (FSFI) questionnaire translated into Arabic  . The results showed no group difference in mean desire score or pain score. However, there were statistically significant differences between the two groups in their scores for arousal, lubrication, orgasm, and satisfaction, as well as the overall sexual function score. A small study of UK women from 13 African countries with high preva- lence of FGM identified a significantly reduced sexual quality of life, based on the Sexual Quality of Life-Female (SQOL-F) questionnaire  . Berg and Denison conducted a systematic review and meta- analysis of the sexual consequences of FGM, combining total of 15 studies with 12 671 participants from seven different countries  . The authors note both the heterogeneity of the available stud- ies as well as their varying methodological quality. However, their meta-analysis results showed that women who had been subjected to FGM were 52% more likely to report dyspareunia, more than twice as likely to report the absence of sexual desire, and a third of recipients reported reduced sexual satisfaction. Long term health consequences of Female Genital Mutilation (FGM)
While it is true that about 10% of women experience Type 3 FGM, other types may also include the removal of the clitoris, which will lead to a reduction in sexual pleasure. A meta-analysis of studies showed that a third of women self-reported reduced sexual satisfaction. Only FGM Type 1a could in any way be compared to male circumcision.