Chart 2. Example of a well-replicated U.S. Import and Export Price Index, 2012–22
Month	Calculated index	Official index
January 2012	100.00	100.00
February 2012	104.68	102.47
March 2012	103.84	107.30
April 2012	104.56	110.66
May 2012	100.34	104.12
June 2012	100.80	93.58
July 2012	101.52	94.76
August 2012	105.59	100.41
September 2012	99.59	106.45
October 2012	98.18	106.69
November 2012	109.43	98.11
December 2012	110.71	97.64
January 2013	108.99	98.88
February 2013	104.81	103.92
March 2013	104.63	103.53
April 2013	111.68	98.97
May 2013	115.92	95.82
June 2013	121.44	96.20
July 2013	120.44	98.97
August 2013	114.20	102.06
September 2013	112.96	103.65
October 2013	112.43	97.73
November 2013	105.16	99.62
December 2013	107.33	105.18
January 2014	107.55	104.57
February 2014	109.53	106.42
March 2014	112.07	108.78
April 2014	108.11	99.88
May 2014	108.69	100.41
June 2014	106.51	98.26
July 2014	107.88	99.47
August 2014	104.89	96.85
September 2014	104.20	96.52
October 2014	97.40	90.66
November 2014	88.96	83.06
December 2014	76.46	72.78
January 2015	61.22	58.32
February 2015	64.57	62.44
March 2015	67.46	65.51
April 2015	63.22	61.03
May 2015	69.58	67.51
June 2015	67.30	67.39
July 2015	64.75	65.13
August 2015	57.09	58.03
September 2015	53.98	54.70
October 2015	53.39	54.23
November 2015	51.73	52.40
December 2015	45.66	46.36
January 2016	41.15	41.27
February 2016	38.72	38.32
March 2016	40.42	39.35
April 2016	41.40	41.27
May 2016	46.97	46.95
June 2016	51.26	52.81
July 2016	48.93	50.99
August 2016	45.55	47.86
September 2016	48.74	51.55
October 2016	53.00	55.38
November 2016	50.74	53.64
December 2016	52.93	55.99
January 2017	54.35	57.11
February 2017	53.80	55.73
March 2017	52.54	54.82
April 2017	54.09	56.94
May 2017	50.54	52.84
June 2017	51.13	53.37
July 2017	50.49	52.99
August 2017	55.31	58.35
September 2017	60.58	63.30
October 2017	57.66	59.88
November 2017	61.67	63.71
December 2017	60.81	62.44
January 2018	64.28	66.39
February 2018	64.46	66.69
March 2018	63.04	64.62
April 2018	65.80	67.54
May 2018	70.24	71.84
June 2018	69.42	71.99
July 2018	70.49	73.05
August 2018	69.92	72.64
September 2018	71.14	73.37
October 2018	76.28	78.17
November 2018	66.60	70.04
December 2018	57.51	60.62
January 2019	55.39	58.94
February 2019	60.29	62.33
March 2019	64.59	66.92
April 2019	66.79	69.31
May 2019	67.13	69.69
June 2019	60.64	63.98
July 2019	63.32	66.51
August 2019	60.49	64.18
September 2019	59.96	63.56
October 2019	60.71	64.30
November 2019	62.57	64.62
December 2019	60.09	63.48
January 2020	63.29	66.42
February 2020	53.47	58.47
March 2020	51.75	55.79
April 2020	33.54	35.91
May 2020	30.06	34.64
June 2020	39.23	42.03
July 2020	41.28	44.59
August 2020	41.39	44.39
September 2020	40.97	44.89
October 2020	40.25	43.95
November 2020	40.43	43.21
December 2020	45.67	48.57
January 2021	50.74	53.49
February 2021	55.20	58.56
March 2021	61.36	65.95
April 2021	60.12	65.13
May 2021	65.11	69.96
June 2021	68.16	72.28
July 2021	69.52	73.78
August 2021	67.46	73.02
September 2021	69.13	74.17
October 2021	76.56	81.27
November 2021	75.48	82.03
December 2021	67.61	73.08
January 2022	75.76	82.30
February 2022	87.60	94.99
March 2022	111.24	117.03
April 2022	108.98	114.70
May 2022	134.86	134.43
June 2022	131.89	140.35
July 2022	112.38	122.06
August 2022	101.20	105.98
September 2022	107.79	105.21
October 2022	115.86	116.14
November 2022	116.26	113.61
December 2022	86.04	89.69
Note: An extremely well replicated index is one that has a correlation coefficient above 0.85, a root-mean-square error less than 2.0, and a mean absolute error less than 1.0 when comparing the short-term relatives of the calculated to the official index. A well-replicated index is one that has a correlation coefficient above 0.2, a root-mean-square error below 5.0, and a mean absolute error less than 2.0. All other indexes are considered not well replicated. Source: U.S. Bureau of Labor Statistics.