How many words does your 17 month old say?

My daughter is 17 months old and is talking a lot or so I thought. I looked up how many words they should be saying by 18 months and it said 68 or something like that. I wrote down all the words she says and she says 47 words and 8. Sentences. Is this enough? Her doctor never said anything about not talking enough. Should I express my concerns with her?