NormalDist.quantiles

Divide into *n* continuous intervals with equal probability.

Returns a list of (n - 1) cut points separating the intervals.

Set *n* to 4 for quartiles (the default).  Set *n* to 10 for deciles.
Set *n* to 100 for percentiles which gives the 99 cuts points that
separate the normal distribution in to 100 equal sized groups.