Remove println() line in your marty function and all will be OK I think.
After removing it I get:
julia> resim()
Total Games:10 Mean Balance:346.12
Total Games:15 Mean Balance:315.99
Total Games:20 Mean Balance:288.535
Total Games:25 Mean Balance:260.39
Total Games:30 Mean Balance:229.455
Total Games:35 Mean Balance:200.685
Total Games:40 Mean Balance:174.51
Total Games:45 Mean Balance:146.775
Total Games:50 Mean Balance:116.83
Total Games:55 Mean Balance:87.255
Total Games:60 Mean Balance:57.7
Total Games:65 Mean Balance:32.285
Total Games:70 Mean Balance:0.92
Total Games:75 Mean Balance:-28.545