Munster lead the way, their average crowd at Thomond Park up more than 3,000 per match on last season when they played four of their eleven home fixtures at Musgrave Park's limited capacity in Cork.
Ulster are up 2,000 and Edinburgh by a thousand with every prospect that their graph will keep climbing on the strength of their best run of the season - three wins in the last four matches.
In many ways, the steepest success in the tricky business of how to win new friends and keep them has been achieved by Connacht. Four years ago, when numbers in Galway had dwindled dangerously close to three figures, Ireland's western province averaged 2,223.
Last season they had more than doubled that figure and now they are still pushing onwards and upwards towards 6,000. They would have been closer to it had last Friday's duel with Edinburgh not been staged on a night wild even for Galway in mid-winter.
Zebre can claim to have increased their home support by almost a third on last season. The Ospreys are also up along with Leinster and if their increase could be counted in a few telephone boxes, the champions are still the best-supported team in the tournament at fractionally short of 20,000.
All told, two-thirds of the GUINNESS PRO12 are on a rising tide of support. Even the four exceptions - the Blues, Dragons, Scarlets and Benetton Treviso - have ample time to turn small shortages into an improvement on last season's figures.
As the competition takes a four-week break until the middle of next month, the race for the top four play-offs could hardly be closer. A mere five points cover five contenders - Ospreys, Warriors, Munster, Leinster and Ulster.
All returned to winning form last weekend, with Leinster and Munster stealing a march on their rivals by securing try-bonus points on the road - Leinster at the expense of the Blues at BT Sport Cardiff Arms Park, Munster against Zebre in Parma.
Ulster's Italian trip turned out to be less than fully rewarded at Treviso despite romping off into a 24-0 lead at the rate of almost a point-a-minute through early converted tries from Paddy Jackson, Ruan Pienaar and Tommy Bowe.
As a reminder that there is no such thing as a foregone conclusion, Treviso found the skill and strength of character for a mighty revival which carried them close to the come-back of the campaign. Tries from Sam Christie and Francesco Minto and four goals from full-back Jayden Hayward added up to 20 unanswered points.
Ulster can only hope that, in the final analysis at the end of the 22-match campaign, the missing bonus point will not cost them a home semi-final or, worse still, a place in the top four.
After losing away derby matches over Hogmanay, the Warriors and the Ospreys made the most of home advantage to resume normal service. The Scarlets made the long trek back to west Wales with nothing to show for their efforts on Clydeside.
Unless they come up with a cure fairly soon, their continuing inability to win away from Llanelli will undermine their prospects of a top-six finish and a reappearance in the Champions Cup next season. The Scarlets have not won a PRO12 match on the road since running in six tries at Treviso almost a year ago.
The Ospreys duly made it ten wins on the bounce at the Liberty Stadium, even if they required five Dan Biggar penalties to see off the Dragons. The Wales fly half has landed 42 goals in eight matches this season, compared to Ian Keatley's 38 for Munster and Ian Madigan's 36 for Leinster.
GUINNESS PRO12 attendances
This season: Average Highest
Leinster ---- 19,668 ---- 43,817 v Munster
Munster ----- 16,002 ---- 25,600 v Leinster
Ulster ---- 15,369 ---- 17,107 v Connacht
Ospreys ---- 8,373 ---- 15,632 v Scarlets
Cardiff Blues -- 7,609 ---- 10,900 v Dragons
Scarlets ---- 7,188 ---- 12,301 v Ospreys
Dragons ---- 6,389 ---- 8,486 v Blues
Warriors ---- 5,883 ---- 6,945 v Edinburgh
Connacht ---- 5,631 ---- 7,745 v Munster
Edinburgh ---- 5,440 ---- 15,810 v Warriors
Benetton Treviso -- 3,297 ---- 4,825 v Zebre
Zebre ---- 2,943 ---- 4,530 v Treviso
Ups and downs on last season
Up:
Munster + 3,263
Ulster + 2,022
Edinburgh + 1,067
Zebre + 905
Connacht + 874
Ospreys + 437
Warriors + 315
Leinster + 19
Down:
Bentton Treviso - 430
Dragons - 385
Cardiff Blues - 370
Scarlets - 105
Last season: Average Highest
Leinster ---- 19,649 ---- 51,700 v Munster
Ulster ---- 13,347 ---- 16,950 v Leinster
Munster ---- 12,739 ---- 20,646 v Leinster
Cardiff Blues -- 7,979 ---- 15,296 v Scarlets
Ospreys ---- 7,936 ---- 13,201 v Scarlets
Scarlets ---- 7,293 ---- 14,796 v Ospreys
Dragons ---- 6,774 ---- 15,205 v Ospreys
Warriors ---- 5,568 ---- 8,855 v Edinburgh
Connacht ---- 4,757 ---- 7,210 v Leinster
Edinburgh ---- 4,373 ---- 10,125 v Warriors
Benetton Treviso -- 3,700 ---- 4,981 v Ospreys
Zebre ---- 2,038 ---- 5,000 v Treviso
The figures apply to the 22-match regulation season. They do not include play-off semi-finals or finals.
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