IV-324 



Figure IV.4.15 



ATTENDANCE AT MAJOR TYPES OF OUTDOOR 

 RECREATION AREAS 



Visits in millions 

 400 



300 

 200 



100 

 80 



60 

 40 



20 



10 

 8 



0.8 

 0.6 



04 



0.2 



1910 



1920 



1930 



1940 



1950 



I960 1965 



Source: Morion Clawson and Jack L. Kultsch, Economics of Outdoor Recreation (Baltimore: 

 John Hopkins Press, 1966), P. 44 



