percentile.py

# usage:
# $ sudo apt-get install python-numpy
# $ python percentile.py 95 97 99 99.9 < my_file_with_floats

import numpy as np
import fileinput
import sys

lines = []
for line in sys.stdin:
    lines.append(float(line[:-1]))

a = np.array(lines)
for p in sys.argv[1:]:
    print "{}: {}".format(p, np.percentile(a, float(p)))