Generate Random recurring json data using python

Need to generate random json data in this format by subtracting the values

list=['20','30','50','1','200']

for n in list : 
    data= 
          {
           "total_members_present":1000    
           "count": n #(here 20) 
           "total_members_now":980 #(1000-n ,n =20),

          },
          {
           "total_members_present":980    
           "count": n #(here 30) 
           "total_members_now":950 #(1000-n ,n =30),

          },

.........

it should continue until the list ends.