def percent_bandwidth(data, period, std=<NUM_LIT>):
catch_errors.check_for_period_error(data, period)<EOL>period = int(period)<EOL>percent_bandwidth = ((np.array(data) -<EOL>lower_bollinger_band(data, period, std)) /<EOL>bb_range(data, period, std)<EOL>)<EOL>return percent_bandwidth<EOL>
Percent Bandwidth.

Formula:
%_bw = data() - l_bb() / bb_range()