An economy's national accounts show the following changes over a financial year:
Calculate the net change in aggregate demand (ADADAD) resulting directly from these changes.
+£21 billion+£21\text{ billion}+£21 billion
+£16 billion+£16\text{ billion}+£16 billion
+£22 billion+£22\text{ billion}+£22 billion
+£27 billion+£27\text{ billion}+£27 billion