Android tablets are closing the gap on Apple. A new study from Strategy Analytics indicates 17.6 million Android tablets shipped worldwide in the first quarter of 2013 compared with 6.4 million shipped in the same quarter last year. Apple shipped 19.5 million iPads worldwide in the first quarter, compared to 11.8 million in the same quarter last year.

Meanwhile, Microsoft has jumped from shipping zero tablets in the first quarter of 2012 to sending out three million in the same quarter this year. All together, Strategy Analytics predicts 40.6 million tablets shipped globally last quarter, nearly a 54 percent increase annually over the 18.7 tablets that shipped in the first quarter of 2012.

In terms of global tablet operating system market share, Strategy Analytics saw iOS controlling 48.2 percent, down considerably from the 63.1 percent it owned in the first quarter of 2012. The Android OS meanwhile crept up to grab 43.4 percent share this quarter, compared to the 34.2 percent it controlled in the first quarter of 2012. Windows jumped from having no presence on tablets a year ago to snagging 7.5 percent of the worldwide share.

Windows’ emergence as a niche player in the tablet market could explain Apple’s significant drop-off in global OS market share. But Apple still managed to increase its global tablet shipments nearly 40 percent annually, which Apple CFO Peter Oppenheimer partly attributed this week during the company’s second quarter earnings call to the iPad Mini rising in popularity. But Microsoft during its most recent earnings report hinted at smaller Surface tablets in the near future, adding another player to the 7-inch tablet market.

Overall, Strategy Analytics saw the annual growth of the global tablet market slow some to 117 percent as compared to 146 percent in the first quarter of 2012.