In [2]:
data.groupby(['Year', 'Full_half']).size().plot(kind='bar', fontsize=16, title='Number of finishers each year')
data.groupby(['Year', 'Full_half']).size()
Out[2]:
Year  Full_half
2013  HM           15340
      MA            4897
2014  HM           16668
      MA            5318
2015  HM            9787
      MA            4667
2016  HM           13757
      MA            5560
2017  HM           15908
      MA            5991
dtype: int64