I actually spent some time thinking about whether to use eighty-eight per cent as another way of saying seven out of every eight women, or whether I should go for eighty-seven-and-a-half per cent.
I was surprised to find how many references to eighty-eight per cent can be found in a Google search, but not as surprised as by the question Did you mean eighty-eight percent?
The Oxford English Dictionary does recognise this orthography, but ‘Chiefly US’ and only when used as a verb – another surprise! And they give only four quotations illustrative of its use, of which my favourite is from 1883: When students are found obtaining help of others they are not percented at all.
Quite right too.
When per cent is used as a noun or adverb the OED insists on keeping the space between the words.
But it’s OK to write about a percentage.
