Histogram - relative frequency

Hi all,

So,

I’m making a histogram

It is of the length of some particles ("particles") vs frequency

Particle length is in the wrong units so I have to multiply the value by 9.77

Anything less than 2 is noise

I want to keep a constant scale (so I can compare samples)

So far I have:

lc = cellfun(@(c) c(end,6),particles);
lcum = (lc*9.77);
goodIndexes = (lcum) >= 2;
histogram(lcum(goodIndexes), 0:25:1000);

I need to change the y values (frequency)(so they are relative to the number of particles)

If, for example, I have 3957 particles, how would I go about dividing the y values by this number?