Russian Wiki gives the following breakdown:
According to an Austrian military archive, upon mobilization in August 14, the Austrian forces consisted of 68.4 divisions. Of them 53.5 divisions (78.1%) headed to the Russian front, 15 divisions (21.9%) to the Serbian. In February 1915 there was 63.5 divisions, of which 51 (80.35) fought against Russians, 8.5 (13.4%) agains Serbians, and 4 divisions (6.3%) stayed at the Italian border.
Upon Italy entering the war, Austria concentrated against it 21 divisions (30.7%), while on Russian front there remained 39.5 (57.7%). On Serbian front there was 8 divisions (11.6%). By February 1916 the contigent dropped sharply at Balkans to 4.9%, and somewhat rose at Russian and Italian fronts (59.2% and 35.9% correspondingly). Half a year later at Russsian front there were 45 divisions (58.6%), and 29.75 (38.9%) at Italian. At Balcans there were just 2 divisions (2.6%).
By February 1917 Austria had 82.25 divisions, of which 59.6% were at the Russian front. ... During the Russian's summer offense of 1917 there were 53.8 Austrian divisions (60.3%). At that time at the Italian front there were 32.75 divisions (36.9%), at Balkans - 2.5 divisions (2.8%). At the truce of Brest there was 43.5 divisions against Russia and 41.25 at Italian front.
15.25 Austrian divisions participated in occupation of Russian territories, while the bulk of the forces (73.8%) were at Italy. 2 divisions remained at Balkans, and 2 more were sent to France.