Table 3.

Summary of drug code changes within the 1998–2016 prescribing datasets, also separated by (current) chapter. Chapter names can be found in table 2

	BNF code change					No product match	No chemical match	Grand total
	Chapter	Section	Paragraph	Sub paragraph	No change
Distinct count of drug name	94	52	560	203	21 258	815	293	23 275
% of drugs	0.40%	0.22%	2.41%	0.87%	91.33%	3.50%	1.26%	100%
% of items	0.04%	0.01%	0.84%	0.51%	97.67%	0.84%	0.10%	100%

Distinct count of drug name by current Chapter
Current Chapter number	Chapter	Section	Paragraph	Sub paragraph	No change	No product match	No chemical match	Grand total
1		4	109		1146	6		1265
2	5	3	4	19	2446	7		2484
3	1	6	19		1132	10		1168
4	42	13	173		3831	9		4068
5	1		161	116	1241	2		1521
6	4	1	2	2	1521	10		1540
7	5		12		528	28		573
8	1		4		579	6	1	591
9	1	7	6	54	4510	507	245	5330
10	27				1041	9		1077
11	1	5	5		571	28	6	616
12					420	44	11	475
13	5	13	28	12	1847	95	30	2030
14			37		195	17		249
15	1				254	37		292
Grand total	94	52	560	203	21 262	815	293	23 279

BNF, British National Formulary.