data = {'Account balances': [{'2008-04-04': 252216},
                      {'2010-05-17': 3619948},
                      {'2010-10-25': 590954},
                      {'2014-10-01': 568340},
                      {'2016-09-04': 2424784},
                      {'2018-08-25': 261463}],
 'Address book contacts': [{'2017-12-05': 20580060}],
 'Age groups': [{'2014-02-17': 37784}, {'2017-12-31': 84011}],
 'Ages': [{'2014-09-01': 1287073}],
 'Apps installed on devices': [{'2017-12-05': 20580060}],
 'Astrological signs': [{'2016-02-29': 27393015}],
 'Audio recordings': [{'2018-08-16': 44109}],
 'Auth tokens': [{'2016-08-07': 2247314}, {'2019-01-03': 17204697}],
 'Avatars': [{'2016-02-21': 144989},
             {'2016-02-29': 1535473},
             {'2016-05-18': 1531235},
             {'2016-05-28': 97151},
             {'2017-11-28': 512311}],
 'Bank account numbers': [{'2015-07-01': 88678}, {'2018-10-21': 242715}],
 'Beauty ratings': [{'2015-11-11': 1100089}],
 'Biometric data': [{'2016-03-27': 228605}],
 'Bios': [{'2018-02-28': 19611022}],
 'Browser user agent details': [{'2008-04-04': 252216},
                                {'2013-01-04': 179967},
                                {'2016-05-20': 104977},
                                {'2016-12-15': 400260},
                                {'2018-07-09': 1279263},
                                {'2018-08-24': 411755},
                                {'2018-12-28': 7633234}],}


for key, value in data.items():
    total = sum(v for row in value for k, v in row.items())
    print(key, total)  # Or add to new data structure?

from copy import deepcopy

data_copy = deepcopy(data)

for key in data_copy:
    list_of_dicts = data_copy[key]
    list_of_tuples = [list(dct.items())[0] for dct in list_of_dicts]
    new_dict = dict(list_of_tuples)
    data_copy[key] = new_dict

print(data_copy)