Hi Sam, nice to meet you.

I think it's pretty standard for a few of the seedlings to not sprout, especially when you're dealing with a high number of seedlings(I'm not sure about the ratio %'s).

If you just had a bag full of randomly mixed seeds and are trying to plant them, then I think it's pretty normal that some seedling do not sprout, turn out bad, or even die.

If you bought them online, then I think the % of seedlings not sprouting are greatly reduced.

A lot of this also depends on how you set up your growing operation, and how effective it is.

If the other seedlings turned out great with no problems and look very healthy then I don't think you should be too worried.