I hate to quote Horace Dediu twice in one day, but sometimes it can’t be helped.

Wednesday’s post on his Asymco blog features the chart at right, which plots Apple’s (AAPL) share price (blue line) over the past four and a half years set against multiples of earnings (15 x EPS, 25 x EPS, etc.). The chart shows that between 2006 and 2008 Apple traded in a range of 35 to 45 P/E. Since late 2008, it’s been stuck between 15 and 25.

“Share prices,” Dediu writes, “normally reflect potential earnings growth and past growth is often a good indicator of near term continuing growth. This is why the P/E is usually a proxy for growth. The faster the growth, the higher the P/E. Or so one would think.”

Dediu writes that the discontinuity indicated in the chart can be traced to the 2008 recession. Several commentators suggest that it may have more to do with concerns about Steve Jobs’ health.

One thing Apple’s current share price does not reflect is the company’s exceptional growth, which rather than slowing down, as its P/E ratio would suggest, has actually accelerated since 2006. Dediu has a chart for this too. See below the fold.

For more analysis from Dediu and some excellent commentary from his readers, click here.

Also on Fortune.com:

• 7 fun facts about Apple’s cash
• Apple clobbers estimates, iPad sales fall short
• Apple’s 92% earnings windfall: The bloggers nail it, the pros miss by a mile

[Follow Philip Elmer-DeWitt on Twitter @philiped]