Table:
0
A
B
C
D
E
F
1
Ecosystem
Date of issue
Place of issue
No. stamps in sheet
Face Value
Printer
2
Sonoran Desert
April 6, 1999
Tucson, Arizona
10
33¢
Banknote Corporation of America
3
Pacific Coast Rain Forest
March 28, 2000
Seattle, Washington
10
33¢
Banknote Corporation of America
4
Great Plains Prairie
March 29, 2001
Lincoln, Nebraska
10
34¢
Ashton-Potter (USA) Ltd
5
Longleaf Pine Forest
April 26, 2002
Tallahassee, Florida
10
34¢
American Packaging Corp. for Sennet Security
6
Arctic Tundra
July 1, 2003
Fairbanks, Alaska
10
37¢
Banknote Corporation of America
7
Pacific Coral Reef
Jan 2, 2004
Honolulu, Hawaii
10
37¢
Avery Dennison
8
Northeast Deciduous Forest
March 3, 2005
New York, New York
10
37¢
Avery Dennison
9
Southern Florida Wetland
October 5, 2006
Naples, Florida
10
39¢
Avery Dennison
10
Alpine Tundra
August 28, 2007
Estes Park, Colorado
10
41¢
Sennett Security Products
11
Great Lakes Dunes
October 2, 2008
Empire, Michigan
10
42¢
Avery Dennison
12
Kelp Forest
October 1, 2009
Monterey, California
10
44¢
Avery Dennison
13
Hawaiian Rain Forest
September 1, 2010
Hawaii National Park
10
44¢
Banknote Corporation of America, Inc

Questions and formulas:
Question: On what date were sheets issued in Tallahassee, Florida?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:F1,C1="tallahassee, florida"),2))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:F13,C2:C13="tallahassee, florida"),2))
Level: medium
Question: Which printer issued sheets on October 5, 2006?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:F1,B1="october 5, 2006"),6))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:F13,B2:B13="october 5, 2006"),6))
Level: medium