Someone

select count(distinct(cust_cod)),no_of_mon from churn where sales_reg = '80' and pack_cod = 'UTH0021' group by no_of_mon;
 count | no_of_mon
-------+-----------
     2 |         6
     9 |         7
    11 |         8
    12 |         9
    17 |        10
    31 |        11
    44 |        12
  1162 |        13
   291 |        14

here i need the sum of count as next column like

count | no_of_mon      total(sum of the count)
-------+-----------
     2 |         6     1579
     9 |         7      1579
    11 |         8      1579
    12 |         9       1579
    17 |        10     1579
    31 |        11      1579
    44 |        12      1579
  1162 |        13       1579
   291 |        14         1579