The lack of any exciting new MacBook laptop computers from Apple in recent months apparently took its toll on third-quarter shipments. Market research firms Gartner and IDC each released their third-quarter PC shipment estimates on Wednesday and as noted by Fortune on Thursday morning, both sets of numbers show an on-year drop in Apple’s U.S. Mac shipments. According to Gartner, Apple shipped 2.16 million Mac computers in the U.S. last quarter, down 2.3% from the 2.21 million units it shipped in the same quarter last year. IDC’s figures show a much more considerable drop, from 2.15 million units in Q3 2012 to 1.91 million last quarter. In either case, Fortune notes that this was the first back-to-school quarter since 2002 that Apple shipped fewer Macs than it did a year earlier.