Примерное решение может быть:
import seaborn as sns, numpy as np
import matplotlib.pyplot as plt
# add the following line if working on jupyter notebook
%matplotlib inline
sns.set()
np.random.seed(0)
x = np.random.randn(100)
ax = sns.distplot(x)
s = 0
for p in ax.patches:
s+= p.get_height()
for p in ax.patches:
ax.text(p.get_x() + p.get_width()/2.,
p.get_height(),
'{}'.format(int(p.get_height()*100/s)),
fontsize=14,
color='red',
ha='center',
va='bottom')
plt.show()
, и вы получите: