I think that percentage is a little off. I went back and looked at the last year of Sport Rocketry articles. Competition oriented articles have an asterisk by the title:
May/June 2020 - 2 competition articles out of 7 (29%)
View from Above: A History of the Science and Hobby of Aerial Photography
TARC Outreach – Wisconsin Youth Rocketry Championship
US/USSR 1988 Spacemodeling Competition Revisited*
Historic Event: F.I.R.E 2019*
The Kid
Interview with Jim Flis, Part 2
NAR Junior Member Science Fair Contest
July/August 2020 - 2 competition articles out of 14 (14%)
NARCON 2020 Overview
Getting Started with Amateur Radio in Hobby Rocketry
Satellite Dreams: Doing Group HPR Projects
How to Win at TARC
FCC Part 15: What you Need to Know
BPS Space 2020: How to Build a Thrust Vectored Model Rocket
High Power Rocketry Safety
Air Launching NASA’s ICON Space Weather Mission
Hot Air: Thermals, Lift and When to Fly*
780 Days in Orbit: Dyna-Soar’s Military Mission Legacy to the X-37B
Secrets of World Class Modeling*
Space Shuttle Solid Rocket Booster
Life Among Titans: A Day in the Life of a Missileer
What is the Mars Snooper?
September/October 2020 - 1 competition article out of 8 (12%)
Spaceport America Cup 2019
Virtual NARCON 2020
Scale Data: Frangible ARCAS*
The Saturn V 50/50 Challenge
Sowing the Seeds of the Future
Modular Avionics Bay
Rocketman Dallas
Book Reviews: The Man Who Ran the Moon, For All Mankind
November/December 2020 - 7 competition articles out of 9 (78%)
Virtual NARAM*
How It Came To Be*
A Tale of Two Altitude Models*
What It Was Like to CD a Virtual NARAM*
Best Midwest Qualified Flight*
Sport Scale*
V-NARAM Results*
Updating the F-61 Starfighter, Part 1
Mike Moran’s Chute Spool
January/February 2021 – 1 competition article out of 7 (14%)
vNARCON Registration
Using an Arduino to Record In-Flight Data
Updating the F-61 Starfighter, Part II
The Arizona Cup, 2020*
An Overview of “Tip to Tip” Fin Lamination
Rocket Motor Certification List
Manufacts
March/April 2021 - 1 competition article out of 8 (12%)
Gravity’s Rainbow: An Intelligent LED Light for Night Flying
Flying 1/2A Altitude*
Fly the Star Trek: First Contact Phoenix
Building and Flying the Omega A
Building a Dumpster Fire
Customizing Rockets using a Cricut
Revitalize your Fleet: Reuse, Rebuild and Refly
Manufacts
Looks like 21 of 62 articles or 34%. YMMV.