I have an output from a FASTA file.

Output:

S: 74803, (5.8%) R: 71819, (5.5%) T: 69645, (5.4%) W: 20019, (1.5%) V: 91683, (7.1%) Y: 36836, (2.8%)

etc...

using this code ...

for key,val in counts.items():

print ("{}: {}, ({:.1%})".format(key,val, val / total))

My questions is how can i sort this so that

a) the biggest percentage numbers ar on top

b) only top 3 results are shown

thanks!