peak_amp = max(data);

largest_peak_amp = max(peak_amp);

x=0:3/1023:3; %0 : roundup(largest_peak_amp)/(number_bins -1): roundup(largest_peak_amp)

[occur,xout]=hist(peak_amp,x);

plot(occur) % plot against channel number
plot(xout,occur) % plot against volts