The September 29, 2015 issue of the Chicago Daily Law Bulletin (accessible at the Law Bulletin's website through a paywall subscription) featured a front page story on the unanimous nature of a large percentage of opinions issued by the Illinois Supreme Court, particularly in civil appeals. The article noted that, according to some court watchers, 86 percent of recent opinions were unanimous.
The story quoted ALA President Michael A. Scodro, former Illinois Solicitor General and currently of Jenner & Block LLP. Scodro noted that unanimous decisions present the state high court with the opportunity to speak "with one voice," which is particularly helpful in cases where lawyers or the public predict a fractured court. The story also quoted past ALA President J. Timothy Eaton, who shared his belief that the supreme court strives to be unanimous on interpretation of both common law and statutory law "so practitioners in the state can know what to expect."