decade with np.floor(), 6x4 genre plot working

#obtain decade list with
decade =  np.floor(data.year / 10) * 10

#6x4 genre plot works by changing to this line
(data[data[genre] == 1].year).hist(ax = ax, bins=bins, histtype='stepfilled', normed=True, color='r', alpha=.2, ec='none')