miRNA-Seq alignment rate

[epi]

I have a 50bp SE mouse miRNA-Seq study, I did quality and adapter trimming, aligned to miRBase v21,

% of uniquely aligned reads is 30-50% across samples, 40% average
about 17-30% aligns non-uniquely

25-50% are unmapped.

Just wondering if it sounds right, any comments form your experience in mice/human experiments.

Thanks

[nucacidhunter]

Your figures are consistent with results that I have seen.