function [stats] = estimate_cell_concentration(files)

  if iscell(files)
    stats = cell(length(files),1);
    for i=1:length(files)
      stats{i} = estimate_cell_concentration(files{i});
    end
    stats = [files(:) stats];

    return;
  elseif (isdir(files))
    content = dir(files);
    newfiles = cell(length(content),1);
    for i=1:length(content)
      if content(i).name(1) ~= '.'
        newfiles{i} = fullfile(files, content(i).name);
      end
    end
    newfiles = newfiles(~cellfun('isempty', newfiles));

    stats = [];
    if numel(newfiles) > 0
      stats = estimate_cell_concentration(newfiles);
    end

    return;
  end

  [dir, name, ext] = fileparts(files);

  if (~strncmp(ext, '.fcs', 4))
    stats = [];

    return;
  end

  [r,h,d]=fca_readfcs(files);
  startt = ((str2num(h.starttime(1:2))*60 + str2num(h.starttime(4:5)))*60 + str2num(h.starttime(7:8)))*1000 + str2num(h.starttime(10:11));
  stopt = ((str2num(h.stoptime(1:2))*60 + str2num(h.stoptime(4:5)))*60 + str2num(h.stoptime(7:8)))*1000 + str2num(h.stoptime(10:11));

  % Seems to yield second like this
  hits = sort(r(:,end) / 10);
  bins = [floor(min(hits)*0.95):ceil(max(hits)*1.05)];
  [counts] = hist(hits, bins);

  outliers = (counts < mean(counts)/3);
  cleaned = counts(~outliers);

  for nneigh = 5:5:15

    F = ones(1,2*nneigh+1);
    F = F/sum(F);

    smoothed = conv(counts(1, :), F, 'same');
    counts = [counts; smoothed];

    smoothed = conv(cleaned(1, :), F, 'same');
    cleaned = [cleaned; smoothed];
  end

  stats = cat(3,[mean(counts, 2) median(counts, 2), std(counts, 0, 2)], [mean(cleaned, 2) median(cleaned, 2), std(cleaned, 0, 2)]);
  figure;plot(bins, counts);title(files);
  figure;plot(bins(~outliers), cleaned);title(files);

  %keyboard

  return;
end