hist

import matplotlib.pyplot as plt
plt.style.use('ggplot')
import numpy as np
D = [100,
    99,
    98,
    98,
    98,
    96,
    96,
    96,
    94,
    94,
    94,
    94,
    94,
    92,
    91,
    90,
    89,
    89,
    89,
    88,
    88,
    87,
    87,
    86,
    86,
    85,
    85,
    85,
    85,
    85,
    84,
    84,
    84,
    84,
    83,
    82,
    82,
    81,
    80,
    79,
    79,
    78,
    77,
    76,
    76,
    74,
    73,
    72,
    68,
    64,
    64,
    64,
    64,
    63,
    63,
    61,
    60,
    58,
    58,
    56,
    54,
    53,
    52,
    46,
    45,
    30]
fig, ax = plt.subplots()
bins=np.arange(min(D), max(D)+2) - 0.5
ax.hist(D, bins)
ax.set_xlabel("Grade(percentage)")
ax.set_ylabel("count")
plt.show()