It's been nearly four years since Google sold its first Nexus device running Android, the Nexus One smartphone, in January 2010.

In smartphone terms, four years can seem like a decade, especially when most smartphones turn over in two years.

Google's Nexus One smartphone first appeared four years ago.

So it's certainly fair to ask: Has Google's Nexus smartphone and tablet series -- featuring no software modifications beyond basic Android and coming unlocked from carriers -- had much of an impact, if not in sales, then in the overall market?

During the last four years, the total Android market, including devices made by several major manufacturers, has grown to dominate global smartphone sales, reaching about 80% of the market, while Android on tablets outdistanced Apple's iPads in 2013, according to IDC.

By comparison, most analysts don't have specific numbers for Nexus device shipments or sales, although they are considered too small to have had a significant impact.

"Google-branded smartphones have not made a material impact in market share. They are in the 'other' category of global smartphones," said Patrick Moorhead, an analyst at Moor Insights & Strategy. The top five makers in recent quarters are Samsung, Apple (on iOS only), Huawei, Lenovo and LG Electronics.

Yankee Group surveyed 16,000 U.S. smartphone customers throughout much of 2013 and found the percentage of those who bought a Google Nexus smartphone in the previous six months was below 5%, while the percentage owning one was less than 1%, but improved in August to 1.04%. The margin of error in its polling is about 1%.

"Google Nexus devices aren't having much of an impact on the market," said Carl Howe, a Yankee Group analyst.

The same can be said of Nexus tablets in terms of market share of all Android tablets. But that misses the point: Robust sales are not Google's ultimate goal in making Nexus gear.

Google's original intent when it devised the Nexus line was to show what an all-Google user experience would be like and to inspire Android makers and developers to make better phones, tablets and Android apps.

"The Nexus line is a hedge against indifference," Moorhead said. "It sends a message to manufacturers that if they can't develop competitive Android products, Google will on their own."

The Nexus One

The original Nexus One, manufactured by HTC, ran Android 2.1, also known as Eclair. Since 2010, Google has ushered in an array of relatively inexpensive yet full-featured smartphones, including the latest, the Nexus 5, built by LG and running Android 4.4 KitKat, that was introduced on Oct. 31.

There are now Nexus tablets in various sizes as well, starting with the first generation Nexus 7, a 7-in. tablet featuring Android 4.1, that went on sale in July 2012.

Nexus tablets and smartphones offer tech-savvy buyers an Android experience devoid of third-party software modifications added by wireless carriers and manufacturers.