function cellphone_population ( )

%*****************************************************************************80
%
%% cellphone_population() plots the US cellphone population over time.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    06 March 2024
%
%  Author:
%
%    John Burkardt
%
  fprintf ( 1, '\n' );
  fprintf ( 1, 'cellphone_population():\n' );
  fprintf ( 1, '  MATLAB/Octave version %s\n', version ( ) );
  fprintf ( 1, '  Plot US cellphone population (percentage) over time.\n' );

  data = csvread ( 'cellphone_population.csv', 1 ) ;

  plot ( data(:,1), data(:,2), 'linewidth', 3 )
  grid on
  xlabel ( '<-- Year -->', 'Fontsize', 16 )
  ylabel ( '<-- Percentage -->', 'Fontsize', 16 )
  title ( 'US Population Cellphone Percentage', 'Fontsize', 16 )
%
%  Save graphics in a file.
%
  filename= 'cellphone_population.png';
  print ( '-dpng', filename );
  fprintf ( 1, '\n' );
  fprintf ( 1, '  Graphics saved as "%s"\n', filename );
%
%  Terminate.
%
  fprintf ( 1, '\n' );
  fprintf ( 1, 'cellphone_population():\n' );
  fprintf ( 1, '  Normal end of execution.\n' );

  return
end

