that is a good point, I was wondering why they used 20% instead of 10%
Ah well.
as for the other parts:
These are the US Law Enforcement Agencies that have the Five Seven it their arsenal.
US Agencies using the 5.7x28mm Weapons
P90
Atlanta, GA PD
Batesburg-Leesville, SC PD
Bellevue, NE PD
Bentonville, AR PD
Benton County, AR SO
Birmingham, AL PD
Bolton, NC PD
Bryan, TX PD
Burbank, CA PD
Camden, SC PD
Charles County, MD SO
Charleston County, SC SO
Chula Vista, CA PD
Columbia, MO PD
Creve Coeur, MO PD
Daleville, AL PD
Denton, TX UNT PD
Doraville, GA PD
Duluth, GA PD
Edina, MN PD
Edmund, OK PD
Grand Forks, ND PD
Greenwood County, SC SD
Hallsville, MO PD
Houston, TX PD
Indianapolis, IN PD
Jacksonville, FL PD
Jefferson County, OH SO
Las Vegas, NV PD
Lawrenceville, GA PD
Lexington, SC PD
Lincoln Borough, PA PD
Little Rock, AR PD
North Little Rock, AR PD
Olathe, KS PD
Palm Beach, FL PD
Palm Beach County, FL SO
Pasco County, FL SO
Ramsey County, MN SO
Richland County, SC SO
Salt Lake City, UT PD
Schenectady, NY PD
Sioux Falls, SD PD
Sparta, NJ PD
Tennessee State Police ERT
US Defense Protective Service
US Federal Protective Service
US Secret Service
Washoe County, NV SO
West Columbia, SC PD
Zephyr Hills, FL PD
Five-seveN
Atlanta, GA PD
Bellevue, NE PD
Benton County, AR SO
Bentonville, AR PD
Birmingham, AL PD
Columbia, MO PD
Creve Coeur, MT PD
Davidson, NC PD
Davis County, UT SO
Duluth, GA PD
Greenwood County, SC SO
Harahan, FL PD
Jennings County, IN SD
Lawrenceville, GA PD
Lexington, SC PD
Lincoln Borough, PA PD
Oakdale, ME PD
Richland County, SC SO
Slidell, LA PD
Whiteoak Burrough, PA PD
P90 or Five-seveN
Atlanta, GA PD
Batesburg-Leesville, SC PD
Bellevue, NE PD
Bentonville, AR PD
Benton County, AR SO
Birmingham, AL PD
Bolton, NC PD
Bryan, TX PD
Burbank, CA PD
Camden, SC PD
Charles County, MD SO
Charleston County, SC SO
Chula Vista, CA PD
Columbia, MO PD
Creve Coeur, MO PD
Creve Coeur, MT PD
Davidson, NC PD
Davis County, UT SO
Daleville, AL PD
Denton, TX UNT PD
Doraville, GA PD
Duluth, GA PD
Edina, MN PD
Edmund, OK PD
Grand Forks, ND PD
Greenwood County, SC SO
Hallsville, MO PD
Harahan, FL PD
Houston, TX PD
Indianapolis, IN PD
Jacksonville, FL PD
Jefferson County, OH SO
Jennings County, IN SD
Las Vegas, NV PD
Lawrenceville, GA PD
Lexington, SC PD
Lincoln Borough, PA PD
Little Rock, AR PD
North Little Rock, AR PD
Oakdale, ME PD
Olathe, KS PD
Palm Beach, FL PD
Palm Beach County, FL SO
Pasco County, FL SO
Ramsey County, MN SO
Richland County, SC SO
Salt Lake City, UT PD
Schenectady, NY PD
Sioux Falls, SD PD
Slidell, LA PD
Sparta, NJ PD
Tennessee State Police ERT
US Defense Protective Service
US Federal Protective Service
US Secret Service
Washoe County, NV SO
West Columbia, SC PD
Whiteoak Burrough, PA PD
Yeadon Borough, PA PD
Zephyr Hills, FL PD
Other manufacturers don't want to make weapons in 5.7 because they don't want to give competitors credit. They'd rather invent their own round that does something similar, which is what HK did with their MP7.
I see 5.7 ammo at every store I go to that sells ammo, except maybe walmart.