£ CDA                                                      Office of Mobile Sources
                                                                        EPA420-B-99-011
                                                                          December 1999
                       Calculation of I/M Waiver Adjusted for CPI
1.  Use of the BLS data:

       CPI adjustment for 1998 =  Average CPI for September 1997 - August 1998
                               Average CPI for September 1988 - August 1989

       Average CPI-U for September 1997 - August 1998 =    1/12 times the sum of the CPI-U for
                                                       each individual month from September
                                                       1997 through August 1998 (inclusive)

       Average CPI-U for September 1988 - August 1989 =    1/12 times the sum of the CPI-U for
                                                       each individual month from September
                                                       1997 through August 1998 (inclusive)

       For example, the Average CPI-U for September 1988 - August  1989 =
              1/12 times (119.8+  120.2+120.3 + 120.5 + 121.1  +121.6  +122.3 +123.1 +123.8
              + 124.1 + 124.4 + 124.6 ) = 122.15

       The Average CPI for 1998 = 162.18

       CPI adjustment for 1998 =  162.18 = 1.3277
                               122.15

2.  The $450 + CPI value = (CPI adjustment for 1998 times $450) = 1.3277 x 450 = $597.48

3.  The data is available at the following Internet Bureau of Labor Statistics CPI home page:
       http://stats.bls.gov/cpihome.htm

       To retrieve the 1989 to 1998 data, select:
          - "Most Requested Series"
          - "Consumer Price  Index-All Urban Consumers (Current Series)"
          - "Consumer Price  Index-All Urban Consumers"
          - Select "U.S. All Items," Years to report for: "1989 to 1999"

       To retrieve the September 1988 to December 1988 data, select:
          - "Table Containing History of CPI-U U.S. All Items Indexes and Annual Percent Changes
          From 1913 to Present." (The direct URL is:
          ftp://ftp.bls.gov/pub/special.requests/cpi/cpiai.txt)

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Year
1989
1995
1996
1997
1998
1999
Average CPI-U
122.2
151.1
155.2
159.5
162.2

Final Waiver
Amount
$450.00
$557.00
$572.00
$588.00
$597.00


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