Tablet vendors shipped 18.7 million units during the third quarter of this year, DigiTimes said on Tuesday. Third-quarter shipments were up 27.5% over the second quarter, but the increase was less than the 60.9% jump in shipments between the first and second quarters of this year. The slower growth was attributed to a weaker global economy, and the entire industry suffered. Apple is estimated to have shipped 13 million units in the September quarter, fewer than DigiTimes’s prediction that Apple would ship 14-15 million units. That figure, however, is still up up 36.8% over the second quarter. 5.7 million non-iPad units shipped during the third quarter, up 10.1% sequentially, but growth suffered due to an “inability to attract customers” away from the iPad, DigiTimes senior analyst James Wong said. Apple’s share of the tablet market grew from 64% in the second quarter to 70% in the third quarter according to DigiTimes’s figures. Apple will reveal its third-quarter earnings on Tuesday evening.