I found some pages where dance weekends list the bands and callers they've booked over the years:

• Austin, Dallas, and Houston
• Atlanta
• Oberlin
• Cincinnati, supplied via email
• Tampa, supplied via email
• BACDS Spring

I used these to try to get a better sense of how the popularity of bands and callers have changed over time. Only Atlanta had data from before 1990 so I started with that year, and I excluded anyone who only called/played once in the dataset, then I looked at it in five-year chunks. Counts (n=N) are the full number of slots in that period, including those played by performers that didn't play often enough to make the main list. Full data is at the bottom of this post.

The main thing I noticed was that the busiest callers are about twice as busy as the busiest bands. I don't know if this means organizers seeking variety more in music than calling, being more ok flying a single person a long way than a whole band with instruments, or musicians playing in multiple configurations, but it's a big difference.

I'd hoped to have more interesting things to say about this data, but it turns out six weekends just isn't enough to shed much light on what happens to the popularity of bands and callers over time.

Bands 1990-1994 (n=15)

2	Wild Asparagus
2	Hillbillies from Mars
2	Fresh Fish
1	Uncle Gizmo
1	Rodney Miller Band
1	Clayfoot Strutters

Bands 1995-1999 (n=34)

5	Nightingale
3	Wild Asparagus
2	Clayfoot Strutters
1	Uncle Gizmo
1	String Beings
1	Rhythm Rollers
1	Red Mountain White Trash
1	Hotpoint Stringband
1	Hillbillies from Mars
1	Footloose

Bands 2000-2004 (n=57)

3	Reckless Ramblers
3	KGB
3	Hotpoint Stringband
3	Airdance
2	Wild Asparagus
2	Popcorn Behavior
2	Hillbillies from Mars
2	Groovemongers
2	Flapjack
2	Footloose
2	Contrarians
2	Bag o Tricks
1	The Guppies
1	String Beings
1	Sevens
1	Rhythm Rollers
1	Red Mountain White Trash
1	Phantom Power
1	Nightingale
1	Moving Violations
1	Latter Day Lizards
1	Fetchin Cat
1	Clayfoot Strutters

Bands 2005-2009 (n=70)

4	Notorious
3	Syncopaths
3	Plum Creek String Band
3	Latter Day Lizards
3	KGB
3	Great Bear Trio
3	Footloose
3	Avant Gardners
2	Rhythm Rollers
2	Nightingale
2	Moving Violations
2	Lift Ticket
2	Hillbillies from Mars
2	Elixir
2	Crowfoot
2	Brittany Bay
2	Black River Ironworks
2	Airdance
1	The Guppies
1	Sevens
1	Phantom Power
1	Moving Violations
1	House Red
1	Hotpoint Stringband
1	Groovemongers
1	Flapjack
1	Fetchin Cat

Bands 2010-2015 (n=84)

6	Elixir
4	Perpetual e-Motion
3	Great Bear Trio
4	Gallimaufry
3	Syncopaths
3	Maivish
3	Latter Day Lizards
2	Clayfoot Strutters
3	Crowfoot
2	Notorious
2	Magic Foot
2	Giant Robot Dance
2	Free Raisins
2	Contra Sutra
2	Coffee Zombies
1	Wild Asparagus
1	Rodney Miller Band
1	Red Mountain White Trash
1	Lift Ticket
1	House Red
1	Footloose
1	Black River Ironworks

Note: including the Dandelion Romp (Oberlin) confuses this data a little because they tended to have an affiliated band they would book every year. So Plum Creek String Band / Black River Ironworks / Gallimaufry show up as very popular on this list, but wouldn't show up at all if you removed Oberlin.

Callers 1990-1994 (n=15)

2	Steve Zakon-Anderson
1	Tony Parkes
1	Scott Higgs
1	Lisa Greenleaf
1	Larry Edelman
1	Kathy Anderson

Callers 1995-1999 (n=33)

3	Robert Cromartie
3	Kathy Anderson
3	George Marshall
3	Cis Hinkle
2	Lisa Greenleaf
2	Becky Hill
1	Tony Parkes
1	Susan Kevra
1	Sue Rosen
1	Steve Zakon-Anderson
1	Scott Higgs
1	Mary Devlin
1	Laurie Andres
1	David Kaynor

Callers 2000-2004 (n=61)

5	Lisa Greenleaf
5	Cis Hinkle
4	Kathy Anderson
3	Joseph Pimentel
3	Peter Amidon
3	Becky Hill
2	Tony Parkes
2	Steve Zakon-Anderson
2	Seth Tepfer
2	Scott Higgs
2	Mary Devlin
2	Larry Edelman
2	George Marshall
2	Beth Molaro
1	Suzanne Giradot
1	Susan Kevra
1	Sue Rosen
1	Robert Cromartie
1	Laurie Andres
1	Kathy Anderson
1	David Kaynor
1	Carol Ormand

Callers 2005-2009 (n=69)

9	Nils Fredland
5	Seth Tepfer
4	Cis Hinkle
3	Sue Rosen
3	Robert Cromartie
3	Lisa Greenleaf
3	Joseph Pimentel
3	Gaye Fifer
3	Carol Ormand
3	Beth Molaro
2	Scott Higgs
2	Rob Harper
2	Rick Mohr
2	Adina Gordon
1	Suzanne Giradot
1	Susan Kevra
1	Mary Devlin
1	Kathy Anderson
1	Becky Hill

Callers 2010-2015 (n=82)

7	Seth Tepfer
7	Nils Fredland
4	Gaye Fifer
3	Susan Kevra
3	Steve Zakon-Anderson
3	Scott Higgs
3	Lisa Greenleaf
3	Diane Silver
3	Cis Hinkle
3	Adina Gordon
2	Sarah Van Norstrand
2	Rick Mohr
2	Luke Donforth
2	Kathy Anderson
2	George Marshall
2	Erik Weberg
2	David Kaynor
1	Sue Rosen
1	Carol Ormand
1	Beth Molaro

I also made stats for the whole period, though this exaggerates the popularity of older callers and bands because they've had more years to be counted. And then it's distorted the other way because the data covers more weekends for the most recent decade. But here it is:

All-Time Bands (n=231)

8	Wild Asparagus
8	Nightingale
8	Elixir
7	Latter Day Lizards
7	Hillbillies from Mars
7	Footloose
6	Syncopaths
6	Notorious
6	KGB
6	Great Bear Trio
6	Clayfoot Strutters
5	Hotpoint Stringband
5	Airdance
5	Crowfoot
4	Rhythm Rollers
4	Perpetual e-Motion
4	Moving Violations
4	Gallimaufry
3	Red Mountain White Trash
3	Reckless Ramblers
3	Plum Creek String Band
3	Maivish
3	Lift Ticket
3	Groovemongers
3	Flapjack
3	Black River Ironworks
3	Avant Gardners
2	Uncle Gizmo
2	The Guppies
2	String Beings
2	Sevens
2	Rodney Miller Band
2	Popcorn Behavior
2	Phantom Power
2	Magic Foot
2	House Red
2	Giant Robot Dance
2	Fresh Fish
2	Free Raisins
2	Fetchin Cat
2	Contrarians
2	Contra Sutra
2	Coffee Zombies
2	Brittany Bay
2	Bag o Tricks

All-Time Callers (n=220)

16	Nils Fredland
15	Cis Hinkle
14	Lisa Greenleaf
14	Seth Tepfer
12	Kathy Anderson
9	Scott Higgs
8	Steve Zakon-Anderson
7	Robert Cromartie
7	George Marshall
7	Gaye Fifer
6	Susan Kevra
6	Sue Rosen
6	Joseph Pimentel
6	Beth Molaro
6	Becky Hill
5	Carol Ormand
5	Adina Gordon
4	Tony Parkes
4	Rick Mohr
4	Mary Devlin
4	David Kaynor
3	Peter Amidon
3	Larry Edelman
3	Diane Silver
2	Suzanne Giradot
2	Sarah Van Norstrand
2	Rob Harper
2	Luke Donforth
2	Laurie Andres
2	Erik Weberg

The data is collated in this sheet if you're curious, but some spelling corrections I've made didn't make it back into there.

(Sorry about the sorting: I don't know an easy way to sort in descending numerical order by ascending alphabetical order. And this way some people that are always last get to be first.)