For the first time, Android-based tablet shipments are expected to overtake those of the iPad. The reason: Smaller-sized devices are catching on with more consumers, according to International Data Corp (IDC).

According to the new report, worldwide iPad shipments will drop to 46 percent in 2013. If correct, this would be the first time shipments have dropped below 50 percent. In 2012, the iPad accounted for 51 percent of all tablet shipments. At the same time, Android tablets are expected to take 49 percent of the market, versus 46 percent last year.

Tablet Projections 2013, 2017

Tablet Projections 2013, 2017

IDC forecasts that 190.9 million tablets will be sold in 2013. Last year, that number stood at 128.3. In 2011, 72 million tablets were sold.

This isn’t the first time that we’ve heard that the iPad’s share of the market was decreasing. In January, it was reported that from October through December, Cupertino’s share of the global tablet market stood at 43.6 percent. One year previously, that number stood at 51.7 percent.

Of course, sales percentages aren’t nearly as important as the number of devices actually sold. Beyond this, profit margins are key.

Note: IDC’s forecasts take into account iPad and iPad mini shipments.