This is from the t'internet...
"It's difficult to say exactly how long it will take to get pregnant. However, these general statistics may give you an idea of how long it will take.
Normally fertile couples have a 20 to 30 per cent chance of getting pregnant each cycle. About 84 per cent of couples in the general population will conceive within one year if they have unprotected, regular sex, and half of the remainder will conceive naturally within the following year, if they keep trying.
This means that while some couples will get pregnant in the first month of trying, for other couples it may take at a couple of years before they conceive. Even then, some healthy couples can take even longer to get pregnant. "