J Manipulative Physiol Ther. 2021 Apr 10;44(3):177–185

Table 1.

Supply of Medicare-Active Spinal Manipulation Providers by Year

Year	Beneficiaries	Chiropractors		Others		All Providers		Variation Between States
		Count	Supply	Count	Supply	Count	Supply	IQR	Mean Supply	SD	Coeff. Var.
2007	45,475,990	47,102	103.58	700	1.54	47,802	105.11	65.88	113.33	49.54	0.44
2008	46,607,357	47,633	102.20	1035	2.22	48,668	104.42	70.26	113.32	49.83	0.44
2009	47,554,332	47,298	99.46	796	1.67	48,094	101.13	70.06	111.52	51.59	0.46
2010	48,730,667	47,187	96.83	880	1.81	48,067	98.64	68.12	109.48	51.48	0.47
2011	50,330,565	47,497	94.37	1385	2.75	48,882	97.12	64.98	108.09	51.59	0.48
2012	52,163,927	47,618	91.29	1858	3.56	49,476	94.85	63.44	105.42	50.52	0.48
2013	53,800,907	47,005	87.37	1835	3.41	48,840	90.78	60.20	101.63	50.69	0.50
2014	55,597,355	46,225	83.14	1636	2.94	47,861	86.09	59.91	97.30	50.27	0.52
2015	57,063,713	45,543	79.81	1,441	2.53	46,984	82.34	55.60	93.90	50.33	0.54
Combined								63.43	106.00	50.65	0.48

All providers = chiropractors + others;

beneficiaries = Medicare Part B enrollees;

coeff. var. = coefficient of variation (SD/mean supply);

count = count of unique providers;

IQR = interquartile range of state supply;

mean supply = mean of all states for that year;

others = providers other than chiropractors;

SD = standard deviation of mean supply;

supply = count per 100 000 Medicare Part B beneficiaries.