In response to Not-A-Shot's comment:
However, if you want to talk history, let's take a look. I found this online, so it might be wrong, but I'm not doing the math to vett the entire list. Teams in bold won the Cup:
Here's a list of every team that has broken 25%
31.88 1977-78 Montreal Canadiens (73/229)
31.72 1975-76 New York Islanders (92/290)
31.28 1977-78 New York Islanders (71/227)
31.15 1978-79 New York Islanders (81/260)
29.73 1973-74 New York Rangers (66/222)
29.34 1980-81 New York Islanders 93/317)
29.25 1982-83 Edmonton Oilers (86/294)
29.03 1969-70 Boston Bruins (81/279)
29.17 1979-80 Montreal Canadiens (77/264)
28.91 1971-72 Boston Bruins (75/256)
28.89 1973-74 Boston Bruins (65/225)
28.79 1972-73 Philadelphia Flyers (74/257)
28.76 1974-75 Boston Bruins (86/299)
28.62 1974-75 Philadelphia Flyers (83/290)
28.46 1987-88 Calgary Flames (109-383)
28.38 1974-75 New York Rangers (84/296)
28.33 1978-79 Montreal Canadiens (68/240)
28.17 1981-82 New York Islanders (80/284)
27.96 1977-78 New York Rangers (78/279)
27.80 1972-73 Boston Bruins (67/241)
27.73 1989-90 Calgary Flames (99/357)
27.68 1970-71 Boston Bruins (80/289)
27.39 1974-75 Buffalo Sabres (83/303)
27.22 1982-83 Chicago Black Hawks (86/316)
27.07 1971-72 Montreal Canadiens (72/266)
27.03 1982-83 Vancouver Canucks (90/333)
26.98 1980-81 Philadelphia Flyers (75/278)
26.91 1980-81 Calgary Flames (81/301)
26.90 1981-82 Calgary Flames (78/290)
26.88 1976-77 Los Angeles Kings (68/253)
26.76 1983-84 Minnesota North Stars (91/340)
26.70 1988-89 Philadelphia Flyers (98/367)
26.69 1981-82 Philadelphia Flyers (79/296)
26.69 1979-80 Los Angeles Kings (83/311)
26.64 1975-76 Boston Bruins (77/289)
26.60 1975-76 Montreal Canadiens (75/282)
26.44 1985-86 Edmonton Oilers (78/295)
26.43 1981-82 Quebec Nordiques (83/314)
26.38 1982-83 Minnesota North Stars (91/345)
26.29 1974-75 Montreal Canadiens (92/350)
25.99 1979-80 New York Rangers (79/304)
25.95 1995-96 Pittsburgh Penguins (109/420)
25.84 1982-83 New York Islanders (69/267)
25.64 1970-71 New York Rangers (71/286)
25.63 1984-85 New York Islanders (71/277)
25.60 1985-86 Chicago Black Hawks (85/332)
25.50 2008-09 Detroit Red Wings (90/353)
25.47 1983-84 Edmonton Oilers (81/318)
25.46 1987-88 Winnipeg Jets (110/432)
25.44 1980-81 Boston Bruins (87/342)
25.44 1975-76 Buffalo Sabres (73/287)
25.36 1985-86 Montreal Canadiens (87/343)
25.26 1984-85 Edmonton Oilers (74/293)
25.24 2008-09 Washington Capitals (79/313)
25.22 2008-09 Washington Capitals (85/337)
25.22 1981-82 Edmonton Oilers (86/341)
25.16 1986-87 Calgary Flames (80/318)
25.09 1969-70 St. Louis Blues (72/287)
25.08 1983-84 New York Rangers (74-295)
25.07 1981-81 Toronto Maple Leafs (85/339)
25.00 1984-85 Calgary Flames (79/316)
I think it's 15 for 61. It's interesting to see that, outside of the '86 Canadiens, all of the teams with the high powerplay conversions and Cups were superteams. Early 70's Bruins, mid-70's Flyers, late 70's Habs, early 80's Islanders, Gretzky's Oilers.
It's also interesting that the last team to have a very high powerplay conversion rate and a Cup was the '86 Habs.
Really interesting NAS. Appears there are definately different dynamics in play nowadays. In the last 10 years, goals are harder to come by, so maybe the pecentages are impacted too. Just a thought. Seems though, pretty much all of the pp leaders, are teams that score well anyway. What seems to be unique about the current Bruins to me, is the fact that they buck the tend by being a a decent scoring team, that can't maintain that role when they have the man advantage. It just makes no sense to me, that it can't be improved upon without reinventing the wheel. I think they're capable of around 17 or 18% and figure somehow, it's likely that will equate to a few more points.
Nice stuff.