It seems as though this thirteen year span covers most of what's usually represented in people's lists.

What percentage of your top 10 is represented by this timeframe? (and if you care to do it and it's easy to access or estimate, top 20,50,100?)

For me, it's 90% of my top 10 (only outlier is The Cars debut), at least 80% of my top 20 (Guided by Voices and The Wrens are in there), and probably at least 70% of my top 100.

This requires having something of a constant list

20-30% of my top ten, and at least 30% of my top 20.

Just checked my original listmania. 66 of the 100 come from between '65 and '77.

100% of my top ten.

The appearance of more recent albums increases at the lower end of the list. No surprise there at all, really - although such things are always in flux and a new list would probably change the ratio a fair bit.

7 of my top 20.

33 of my top 100.

1. The Rolling Stones - Exile on Mainstreet
2. The Rolling Stones - Sticky Fingers
3. The Rolling Stones - Aftermath
4. The Rolling Stones - Let it Bleed
5. The Rolling Stones - Beggar's Banquet
6. The Rolling Stones - Some Girls
7. The Rolling Stones - Goats Head Soup
8. The Rolling Stones - It's Only Rock and Roll
9. The Rolling Stones - Tattoo You
10. Bob Dylan - Bringing It All Back Home

The only outlier is Tattoo You - released in 1981, but mostly re-jiggered outtakes from the 70s.

If you love The Stones so much, why don't you marry them.

For the same reason you can't come to grips and admit your abject failure at life?

I just looked back at my listmania and was surprised at the results:

0% of top 10,
10% of top 20
26% of top 50

80% of my top 10 (exceptions were Gang of 4 - Entertainment & The Clash - s/t (us version))
85% of my top 20
71% of my top 100

according to my last listmania. The %'s would be even higher if I'd limited my list to rock.

Roughly 70% of my Top 20 is <1977.

11 out of 20 of my last listmania came out during that period and a couple more were close.

Oh, I believe I came to grips with that. I even reached the point where I can admit my favorite college football team won't win forty some titles in a row and will most likely lose once again to their rival this year.

60-70% of my current top 10.

Whatever my current top 10 is.

Rock. Chalk. Jayhawk.

... Oh, you meant Oklahoma? That, too, prolly.

Yeah, no disrespect to Kansas, who may very well win the Big 12 North, but Oklahoma is the historic rival.
If the game was in Lincoln again, I'd easily take Nebraska with a new QB versus a suspect KU Defense. Since the Jayhawks scored more than 70 against Nebraska the last time in Lawrence, I can't be cocky.

Probably 1/3rd, maybe 1/2. I don't actually have a list.

2. The Who – Who’s Next (1971)
3. Cheap Trick – Cheap Trick (1977)
6. Steely Dan – The Royal Scam (1976)
7. Willie Nelson – Shotgun Willie (1973)
10. Nilsson – Nilsson Schmilsson (1971)

50%

These are all 1971-1977, so I guess 1965-1970 didn't make as much of an impression on me.

My number 8

based on my listmania (the easiest way to figure this out), 1 from my top 10 falls within those years (Fingerprince by The Residents, #4 on my list), and 2 within my top 25 (the addition of First Utterance by Comus). Which doesn't surprise me... at all.

This would make my brain hurt to try and figure out.

hell, I don't even remember my lists to begin with. But given my penchant towards 60's and 70's stuff I'm assuming it would be mucho high.

maybe 2 or 3 that i can think of.

As for the rest of my list,

Top 25 = 7 (28%)
Top 50 = 9 (18%)
Top 100 =14 (14%)

So, while I don't have a ton of stuff from that timeframe on my list, what I do have is mostly ranked pretty highly.

wow, just looking at my list, I clearly dont think as highly of music from 65-77 as i do newer stuff.

I only have 9 albums in my top 100 from that period

(Everybody knows this is nowhere, Zuma, Obscured by Clouds, Crime of the Century, Animals, Even in the quietest moments, Dreams dreams dreams, On the beach, and Space is the place)

only one in my top ten (EKTIN)
and
only 4 in my top fifty

across all genres -

43% (65-77)
37% (post '77)
20% (pre '65)

80% of my top 10 = 65-77
20% of my top 10 = pre '65)

I figured the period in question would've scored higher, but I was wrong.