So nobody should be surprised, especially with competition in the tablet market heating up, if the breakneck growth in iPad unit sales that Apple reported in Q3 2011 and Q3 2012 — 183% and 84%, respectively — slowed to a crawl in Q3 2013.

A slow crawl is good way to describe what Fortune‘s panel of Apple analysts is expecting. Among the 48 we’ve heard from so far — 29 Wall Street professionals and 19 amateurs — the average estimate for fiscal Q3 iPad sales is 18.1 million.

That would represent a paltry 6.2% growth year over year. Revenue from Apple’s iTunes/Software/Services line item is growing four or five times faster than that.

There is, however, considerable disagreement among the bulls and bears in our analyst pool.

• The high estimate of 22 million iPads, submitted by independent Paul Reina of the Braeburn Group, would represent a yearly growth rate of nearly 30%.
• The low estimate of 13.5 million from Pacific Crest’s Andy Hargreaves is 21% below last year’s sales.

We’ll find out who was closest to the mark when Apple reports its earnings for fiscal Q3 2013 after the markets close on Tuesday, July 23.

Below: The individual analysts estimates, with the pros in blue and the indies in green. Thanks as always to Posts at Eventide‘s Robert Paul Leitao for pulling together the Braeburn Group numbers.