Matplotlib と Pandas を使用して、正しい間隔と正確な注釈を備えたグループ化棒グラフを作成するにはどうすればよいですか?

for p in ax.patches:
    ax.annotate(f'{p.get_height():0.2f}', (p.get_x() + p.get_width() / 2., p.get_height()), ha = 'center', va = 'center', xytext = (0, 10), textcoords = 'offset points')

import pandas as pd
import matplotlib.pyplot as plt

df = pandas.DataFrame({
    'Very interested': [1332, 1688, 429, 1340, 1263, 1629],
    'Somewhat interested': [729, 444, 1081, 734, 770, 477],
    'Not interested': [127, 60, 610, 102, 136, 74]
    }, index=['Big Data (Spark / Hadoop)', 'Data Analysis / Statistics', 'Data Journalism', 'Data Visualization', 'Deep Learning', 'Machine Learning'])

colors = ['#5cb85c', '#5bc0de', '#d9534f']
fig, ax = plt.subplots(figsize=(20, 8))

ax.set_ylabel('Percentage', fontsize=14)
ax.set_title(
    "The percentage of the respondents' interest in the different data science Area",
    fontsize=16)
ax.set_xticklabels(ax.get_xticklabels(), rotation=0)

df.plot.bar(ax=ax, color=colors)

for p in ax.patches:
    ax.annotate(f'{p.get_height():0.2f}', (p.get_x() + p.get_width() / 2., p.get_height()), ha='center', va='center', xytext=(0, 10), textcoords='offset points')

plt.show()