Very, very few college or pro meets compile attendance data. FIFA : corruption :: track : incompetence. Also, you're lazy--most of this is relatively easy to track down--and I expect part of your paycheck.
For 2015...
Penn Relays:
Thursday: 22,537
Friday: 39,130
Saturday: 48,920
Total: 110,587
Source: Track Newsletter
Drake Relays:
Thursday: 5,791
Friday Morning/Afternoon: 9,672
Friday Night: 10,770
Saturday: 14,504
Total Attendance: 40,737
Source:
http://www.godrakebulldogs.com/ViewArticle.dbml?&ATCLID=210037098&DB_OEM_ID=15700
Texas Relays:
"Attendance for the four-day meet was 41,253, which included a crowd of 20,299 Saturday and 15,529 Friday".
Source:
http://www.texassports.com/news/2015/3/26/relays_0326155711.aspx?path=relays
Prefontaine Classic:
yet to take place, usually between 14,000 and 15,000
After those, the best-attended meets are state high school championships. As for college or pro meets, it's slim pickings. Global Athletics doesn't release attendance figures because they obviously don't care whether anyone shows up to their meets or not. Millrose doesn't release figures but is usually a sellout or darn close, figure 5,000+, maybe something similar for the Armory Invitational. And besides that, what pro meets are there in this country?
As far as college meets go, the only place that regularly releases outdoor attendance data is Oregon. Arkansas, Texas A&M and occasionally Notre Dame release indoor attendance figures. Mt. SAC probably has decent attendance but they've never announced a number. Even a few years ago, the USC-UCLA dual would bring in thousands but no numbers have been released from that meet for a while.
"I don't doubt the Saturday attendance figure of of 7,322 for the Oregon Relays at Hayward Field -- assuming the school counted all the participants as part of the total."
Source: Ken Goe, The Oregonian
http://www.oregonlive.com/trackandfield/index.ssf/2014/04/the_oregon_relays_was_a_good_m.html
Oregon Twilight: 5,717
Source:
http://www.oregonlive.com/trackandfield/index.ssf/2015/05/matthew_maton_delights_the_ore.html
Oregon vs Washington vs Kentucky: 3,428
Source:
http://www.oregonlive.com/trackandfield/index.ssf/2015/04/monday_morning_news_notes_link_15.html