How devoted are Apple users to the Apple ecosystem?

The bar at top represents entire user population. The left pie chart shows the 6% who are “devoted” to a particular mobile ecosystem. The right pie chart shows the 9% who are merely “loyal.” Source: Forrester Research Inc. Click to enlarge.

FORTUNE — According to a Forrester survey released this week, the vast majority of computer users (85% worldwide, 88% in the U.S.) have little or no loyalty to a particular mobile computing ecosystem — the nexus of devices, software, services and sheer muscle memory that tie a user to one vendor or another.

Among those users who show any loyalty at all, Apple (AAPL) dominates. No big surprise there. What is a little surprising — or at least new — is what that loyalty looks like when measured quantitatively and served up in pie charts like the one above.

To take the full measure of ecosystem devotion, Forrester’s Charles Golvin divided the user population into three groups:

  • The Free Radicals, who have little to no loyalty. This group consists of two subgroups: those who own exactly one type of device and those who own multiple devices, all of which come from a different ecosystem.
  • The Loyalists, who have moderate or divided loyalty. This group is made up of those using multiple devices, a majority of which — but not all — are tied to a single ecosystem.
  • The Devotees, who are strongly loyal to a single ecosystem. This segment consists of those using multiple devices, all of which come from a single ecosystem.

As the pie chart above shows, Apple users represent 58% of the world’s loyalists and 56% of its devotees. Among U.S. consumers, its dominance is even greater: 59% of loyalists and 71% — repeat, 71% — of devotees.

Microsoft (MSFT) is a contender in the devotee category (44% global info workers, 27% U.S. consumer), largely because Windows is still has a firm grip on 85% of the workplace PC market.

Google (GOOG), thanks to Android’s majority share of the global smartphone market and growing share in tablets, has its loyalists — 17% globally and 10% in the U.S. But until Chromebooks catch on, the number of Google devotees will remain, in Golvin’s words, “vanishingly small.”

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