Image source: Apple.

In what now seems like ancient history, Apple (NASDAQ:AAPL) launched the original iPhone in 2007. At the time, the smartphone landscape looked very different than it does now, but the market was ripe for disruption, because most smartphones were not consumer-friendly devices. Smartphones used to be reserved for power users and professionals, but Apple was able to catalyze mainstream adoption by average consumers by making its device more approachable and intuitive to use.

Apple has been quite successful in selling an increasing number of iPhone units every year thanks to an ongoing cycle of new industrial designs, improved performance, and innovative new features. The iPhone has become Apple's most important business by a large margin, and a global business selling into smartphone markets all around the world.

As of last quarter, Apple has sold a cumulative lifetime total of 821.8 million iPhones.

iPhones sold
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Here is a breakdown of the iPhone's performance since the beginning of 2012.

Quarter

iPhone Units Sold

Cumulative Lifetime Units Sold

Q1'12

35.1

218.1

Q2'12

26

244.2

Q3'12

26.9

271.1

Q4'12

47.8

318.9

Q1'13

37.4

356.3

Q2'13

31.2

387.5

Q3'13

33.8

421.3

Q4'13

51

472.4

Q1'14

43.7

516.1

Q2'14

35.2

551.3

Q3'14

39.3

590.6

Q4'14

74.5

665

Q1'15

61.2

726.2

Q2'15

47.5

773.7

Q3'15

48

821.8

Source: SEC filings. Calendar quarters shown. Unit figures in millions.

Apple's product strategy for the iPhone also continues to evolve. For many years, Apple used to release just one model per year, but now the company launches multiple models per year in order to address broader market segments. Still, Apple remains highly focused compared to smartphone rivals that may release dozens of different models per year.

Evan Niu, CFA owns shares of Apple. The Motley Fool owns shares of and recommends Apple. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.