In a bid to improve that unwelcome statistic Glasgow have appointed Gary Mercer as a full-time defensive coach.
Mercer won 22 rugby-league caps for the Kiwis, and resigned as head coach with Oldham to take up the challenge. He will also be working with Scotland's under-19 and under-21 squads, but he insists that Glasgow will provide his priority.
"Defence is a personal thing, and it's a mind thing," Mercer insisted in today's Scotland on Sunday. "If the individual doesn't buy into it, how can the system work on a collective basis? There are lots of players at Glasgow that need to work on defence, and I am doing plenty of one-on-one with the boys.
"Even if someone is poor technically, if we can get them enthusiastic about defence, get them running up fast and closing down space, then they can do their bit. It's my job to pull the right triggers, find out what makes them tick."
Mercer continued: "I played union until the age of 16, but I am learning from the Glasgow coaches as much as I am teaching the players. They are buying into me and vice versa. I do believe that I can make a difference, but it will be a challenge. It won't happen overnight: we will probably need three of four matches for the guys to buy into what I'm about."