A = [[12606.0, 74204.0, 56.0, 64.0, 72.0, 21.6, 18.0, 0.0, 0.0], 
     [12606.0, 105492.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 45.6], 
     [12606.0, 112151.0, 2.4, 4.0, 0.0, 0.0, 0.0, 0.0, 0.0], 
     [12606.0, 121896.0, 0.0, 0.0, 0.0, 0.0, 0.0, 60.8, 0.0],
     [12901.0, 74204.0, 25.0, 15.0, 45.0, 38.6, 18.0, 0.0, 0.0], 
     [12901.0, 105492.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 45.6]]
 
from collections import defaultdict
d = defaultdict(list)
for row in A:                 
    d[row[0]].append(row[2:])   # append all rows with same ID number.
 
print {k:[sum(col) for col in zip(*rows)] for k, rows in d.items()}

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