Oksélé. My first inadequate 3d bar plot with matplotlib

myfirstinadequate3dbar.py

# encoding: utf-8
import matplotlib.pyplot as plt
from matplotlib.ticker import FormatStrFormatter
import numpy as np
import codecs
import pylab

fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')

RANGE = 20
CSV_FNAME = 'prix_train_sens.csv'

with codecs.open(CSV_FNAME, 'r', encoding='utf-8') as csv_handle:
    title_line = csv_handle.next()
    titles = [title.replace('"', '') for title in title_line.split('*')][2:]


table = np.genfromtxt(CSV_FNAME,
    skip_header=3,
    usecols=(2, 3, 4, 5, 6),
    skip_footer=13,
    delimiter=',')

table = table.transpose()

def line_is_minimum_for_col(line_index, col_index):
    col_data = table[:, col_index]
    col_min = col_data.min()
    return table[line_index, col_index] == col_min


col_nbs = np.arange(20)


for index, line in enumerate(table):
    print "index: %i - " % index, titles[index], line
    colors = [
            'g'
            if line_is_minimum_for_col(index, col_index)
            else 'r'
            for col_index in col_nbs
            ]
    ax.bar(col_nbs, line, zs=index, zdir='y', color=colors, alpha=0.8)
    for column, value in enumerate(colors):
        if value == 'g':
            text = '%f' % table[index, column]
            label = pylab.annotate(text,
                    xycoords='data',
                    xy = (1, 2),
                    textcoords = 'offset points', ha = 'right', va = 'bottom',
                    bbox = dict(boxstyle = 'round,pad=0.5', fc = 'yellow', alpha = 0.5),
                    arrowprops = dict(arrowstyle = '->', connectionstyle = 'arc3,rad=0'))


yticks = np.arange(len(table))
ax.set_yticks(yticks)
ax.set_yticklabels(titles)

ax.set_xlabel(u'Nombre de trajets par mois sur 11 mois', labelpad=300)
ax.set_ylabel(u"\n"*15 + u"Type d'abonnement")
ax.set_zlabel(u'\n'*4 + u'Prix annuel', labelpad=300)
ax.zaxis.set_major_formatter(FormatStrFormatter(u'%d €'))

for w_axis in (ax.w_xaxis, ax.w_yaxis, ax.w_zaxis):
    w_axis.gridlines.set_lw(3.0)
    w_axis._axinfo.update({'grid' : {'color': (0, 0, 0.75, 0.2)}})

plt.show()

note: annotations seem not to work in my graph