[Mark McLeod]

Here is everywhere, including what you've all contributed.
This is rough and has no guarantee of accuracy, but it's a ballpark summary.
Those who contributed understand how arbitrary the cutoff can be between home & away teams.
I put the rough criteria in the attached spreadsheet with the summary data.

Event --------------------- #Teams - #Local - #Away - % away - Rookies - Not at '10 Event

BAE/Granite State Regional --- 53 ---- 44 ----- 9 ---- 17% ----- 8% ---------- 25%
New Jersey Regional ----------- 60 ---- 44 ---- 16 ---- 27% ----- 8% ---------- 30%
Finger Lakes Regional --------- 44 ---- 31 ---- 13 ---- 30% ----- 9% ---------- 27%
Alamo Regional ---------------- 60 ---- 55 ----- 5 ----- 8% ---- 32% --------- 100%
San Diego Regional ------------ 59 ---- 44 ---- 15 ---- 25% ---- 22% ---------- 47%
Florida Regional --------------- 63 ---- 58 ----- 5 ----- 8% ---- 32% ---------- 43%
WPI Regional ------------------ 34 ---- 17 ---- 17 ---- 50% ----- 6% ---------- 50%
Lake Superior Regional -------- 42 ---- 41 ----- 1 ----- 2% ---- 21% --------- 100%
Greater Kansas City Regional - 55 ---- 47 ----- 8 ---- 15% ----- 9% ---------- 16%
Pittsburgh Regional ----------- 35 ---- 20 ---- 15 ---- 43% ---- 11% ---------- 40%
Wisconsin Regional ------------ 53 ---- 32 ---- 21 ---- 40% ----- 8% ---------- 32%
New York City Regional ------- 65 ---- 44 ---- 21 ---- 32% ----- 6% ---------- 28%
Israel Regional ---------------- 52 ---- 50 ----- 2 ----- 4% ---- 10% ---------- 13%
Arizona Regional -------------- 45 ---- 45 ----- 0 ----- 0% ---- 13% ---------- 13%
Sacramento Regional ---------- 47 ---- 35 ---- 12 ---- 26% ---- 23% ---------- 47%
Peachtree Regional ------------ 49 ---- 44 ----- 5 ---- 10% ---- 20% ---------- 33%
Boilermaker Regional ---------- 41 ---- 35 ----- 6 ---- 15% ---- 12% ---------- 24%
Bayou Regional ---------------- 40 ---- 34 ----- 6 ---- 15% ---- 30% ---------- 45%
Chesapeake Regional ---------- 63 ---- 32 ---- 31 ---- 49% ----- 8% ---------- 49%
Saint Louis Regional ---------- 31 ---- 25 ----- 6 ---- 19% ---- 26% ---------- 35%
Oklahoma Regional ------------ 52 ---- 48 ----- 4 ----- 8% ---- 13% ---------- 19%
Lone Star Regional ------------ 57 ---- 57 ----- 0 ----- 0% ---- 28% ---------- 32%
Seattle Olympic Regional ------ 50 ---- 35 ---- 15 ---- 30% ---- 36% ---------- 64%
Seattle Cascade Regional ------ 48 ---- 46 ----- 2 ----- 4% ---- 17% ---------- 21%
Waterloo Regional ------------- 29 ---- 21 ----- 8 ---- 28% ----- 7% ---------- 34%
Los Angeles Regional ---------- 63 ---- 59 ----- 4 ----- 6% ---- 11% ---------- 17%
Washington DC Regional ------ 49 ---- 33 ---- 16 ---- 33% ----- 6% ---------- 33%
Hawaii Regional --------------- 29 ---- 26 ----- 3 ---- 10% ---- 17% ---------- 21%
Midwest Regional -------------- 51 ---- 34 ---- 17 ---- 33% ---- 12% ---------- 37%
SBPLI Long Island Regional --- 50 ---- 43 ----- 7 ---- 14% ----- 6% ---------- 18%
Autodesk Oregon Regional ----- 60 ---- 36 ---- 24 ---- 40% ---- 13% ---------- 30%
Palmetto Regional ------------- 46 ---- 25 ---- 21 ---- 46% ---- 11% ---------- 57%
Greater Toronto West Regional - 36 ---- 34 ----- 2 ----- 6% ---- 25% ---------- 36%
Greater Toronto East Regional - 36 ---- 29 ----- 7 ---- 19% ---- 31% ---------- 47%
Silicon Valley Regional -------- 44 ---- 42 ----- 2 ----- 5% ----- 9% ---------- 14%
Connecticut Regional --------- 53 ---- 38 ---- 15 ---- 28% ---- 17% ---------- 34%
10,000 Lakes Regional -------- 62 ---- 53 ----- 9 ---- 15% ---- 15% ---------- 29%
North Star Regional ----------- 59 ---- 48 ---- 11 ---- 19% ---- 14% ---------- 37%
Las Vegas Regional ------------ 42 ---- 11 ---- 31 ---- 74% ----- 5% ---------- 43%
Smokey Mountain Regional ---- 50 ---- 15 ---- 35 ---- 70% ---- 30% --------- 100%
Colorado Regional ------------- 45 ---- 37 ----- 8 ---- 18% ---- 16% ---------- 29%
Boston Regional --------------- 45 ---- 40 ----- 5 ---- 11% ---- 13% ---------- 27%
North Carolina Regional ------- 51 ---- 36 ---- 15 ---- 29% ---- 33% ---------- 65%
Buckeye Regional -------------- 57 ---- 42 ---- 15 ---- 26% ---- 12% ---------- 30%
Philadelphia Regional ---------- 57 ---- 36 ---- 21 ---- 37% ----- 4% ---------- 35%
Dallas East/West Regional ----- 48 ---- 47 ----- 1 ----- 2% ---- 33% ---------- 35%
Utah Regional ----------------- 28 ---- 28 ----- 0 ----- 0% ---- 25% ---------- 25%
Virginia Regional -------------- 60 ---- 53 ----- 7 ---- 12% ----- 7% ---------- 22%