Apple's foothold as the leader of the worldwide smartphone operating system market has declined year-over-year in the second quarter of 2013 with Android now firmly above the California tech giant's iOS. Meanwhile, Windows Phones are showing slight increases against Apple's declining sales according to new data from IDC.

Overall a total of 236.4 million smartphones were shipped to various consumers in the second quarter of this year. This number was up 51.3 percent from 156.2 million units shipped during the same quarter last year. Smartphone shipments also grew 9.3 percent over the first quarter of this year.

The best smartphone operating system this quarter turned out to be Android, which grabbed an impressive 79.3 percent of the smartphone OS market. Android's numbers were up from 69.1 percent this time last year. The Google powered operating system was able to take this much of the market thanks to solid sales of the Samsung Galaxy S4, the flagship phone that's been beating Apple's iPhone left and right since it came out. However, PCMag also attributes Android's success to gains made by LG, Huawei, Lenovo and ZTE, each of these companies saw significant improvement in unit shipment volumes in the tens of millions.

While Android moved up, Apple took a step down going from 16.6 this time last quarter to 13.2 this time around. Researchers from IDC believe the dip was caused by a lack of new devices from Apple.

"Without a new product launch since the debut of the iPhone 5 nearly a year ago, Apple's market share was vulnerable to product launches from the competition. But with a new iPhone and revamped iOS coming out later this year, Apple is well-positioned to re-capture market share," Ramon Llamas, research manager with IDC's mobile phone team, said in a statement reported by PCMag.

Surprisingly enough, Windows Phones came in third, beating out BlackBerry. The company saw its largest year-over-year increase among the top five smartphone competitors. According to IDC, Windows Phones received a 3.7 percent share of the smartphone OS market, which was up from 3.1 from the second quarter of 2012. Many believe this is a direct result of the Nokia Lumia's success.

"Last quarter we witnessed Windows Phone shipments surpassing BlackBerry and the trend has continued into the second quarter. Nokia has clearly been the driving force behind the Windows Phone platform and we expect that to continue," said Ryan Reith, program manager with IDC's Mobility Tracker Programs.