class_docstr: Divide a column into 100 equal-size groups using the "CDF" method.
  
  See `this explanation <http://www.amstat.org/publications/jse/v14n3/langford.html>`_
  of the various methods for computing percentiles.
  
  "Zeroth" (min value) and "Hundredth" (max value) percentiles are included
  for reference and intuitive indexing.
  
  A reference implementation was provided by
  `pycalcstats <https://code.google.com/p/pycalcstats/>`_.
  
  This aggregation can not be applied to a :class:`.TableSet`.
  
  :param column_name:
      The name of a column containing :class:`.Number` data.
code: def __init__(self, column_name):
      self._column_name = column_name
  
file_path: agate/agate/aggregations/percentiles.py
imports: import math
  from agate.aggregations.base import Aggregation
  from agate.aggregations.has_nulls import HasNulls
  from agate.data_types import Number
  from agate.exceptions import DataTypeError
  from agate.utils import Quantiles
  from agate.warns import warn_null_calculation
label_desc: Use image node_id 1 to create a new Percentiles object from inherited base classes: Aggregation with example: obj = Percentiles(column_name)