89% of advertisements had a male voice-over.是什么意思？

89% of advertisements had a male voice-over.

89％的广告旁白都是男声。

of

prep. 关于，属于…的，由…制成；aux. 助动词 [非标准用语、方言] =have [主用于虚拟语气]；

例句
He did have a real knowledge of the country...
他对该国的确知之甚多。

advertisements

n. 出公告，做广告( advertisement的名词复数 )；

例句
The beer is bitterer, the coins are heavier, the grass greener, the advertisements are more blatant.
啤酒更苦, 硬币更重, 草更绿, 广告更讨厌.

had

v. 有（ have的过去式和过去分词 ），（亲属关系中）接受，拿，买到；

例句
He claimed that his parents had abandoned him...
他声称父母遗弃了他。

male

adj. 男性的，雄性的，有力的，[植]雄性的，仅有雄蕊的；n. 男，雄性动物，[植]雄性植物，马累[马律]；

例句
I say 'boys' advisedly because we are talking almost entirely about male behaviour...
我特意说成“男孩们”因为我们几乎一直在讨论男性的行为。