Android, Windows Phone Tablets Rise 18% as Apple's iPad Declines

Sales of

iPad dropped to 14.6 million units during Q2 2013, resulting in a 25 percent decline from the previous quarter.

The sales slump caused Apple's market share to

-- the lowest ever since the iPad was introduced more than three years ago. According to

, shipments of non-iOS tablets (ex: those made with

(NASDAQ:

) Android,

Windows or other mobile operating systems) rose 18 percent during the second quarter.

While angry investors have quietly accused Android tablet suppliers of flooding the market with more devices than consumers demanded, that does not appear to be the case here. During the June quarter in 2012, for example, non-iOS tablet shipments amounted to just five million units. Apple sold

that quarter, setting a new record. While iPad sales did not continue to grow during Q3 2013, they came in at

, which was considered to be a respectable number at the time. According to DigiTimes' figures, non-iOS tablets experienced strong growth, rising to 11.5 million units shipped. When the iPad Mini and fourth-generation iPad were released in Q4 2012, Apple experienced

, selling 22.9 million units. Non-iOS tablet makers

22.2 million tablets during the same period. Things changed during Q1 2013. Apple continued to break quarterly sales records by selling

. Non-iOS tablet shipments took a dive, however, falling to just 12.4 million units. The trend reversed itself during Q2 2013, a time when Apple sold just 14.7 million units. Non-iOS tablet makers shipped 14.6 million devices to retail. Thus, the question becomes this: if non-iOS shipments are not indicative of the final sales, why would the shipments have plummeted so sharply during the first quarter while Apple's sales continued to rise? And why would non-iOS tablet shipments increase so heavily during the second quarter at a time when consumers are losing interest in the iPad?