A little (<6%) slower than fraction_correct due to the data extraction overhead.

def fraction_correct_pandas(dataframe, x_series, y_series, x_cutoff = 1.0, y_cutoff = 1.0, ignore_null_values = False):
    '''A little (<6%) slower than fraction_correct due to the data extraction overhead.'''
    return fraction_correct(dataframe[x_series].values.tolist(), dataframe[y_series].values.tolist(), x_cutoff = x_cutoff, y_cutoff = y_cutoff, ignore_null_values = ignore_null_values)