Strangely enough, most are.
"What was surprising was how often they agreed to agree. Two-thirds of the 72 cases fully decided this term were unanimous, the highest percentage in years. Most were low-profile disputes, but did include:"
http://wtvr.com/2014/07/01/supreme-court-had-highest-percentage-of-unanimous-decisions-this-session/
I didn’t know that. It’s just the “politically charged” ones that are split...