Conformational studies on ethane-1,2-diol (COCH2-CH2OH) have shown the most stable conformation about the central C-C bond to

Question:

Conformational studies on ethane-1,2-diol (COCH2-CH2OH) have shown the most stable conformation about the central C-C bond to be the gauche conformation, which is 9.6 kJ/mol (2.3 kcal/mol) more stable than the anti conformation. Draw Newman projections of these conformers and explain this curious result.