ChemTok: A New Rule Based Tokenizer for Chemical Named Entity Recognition

Table 2

Details of BioCreative data set.

Data set	Number of abstracts	Number of sentences	Number of NEs in each class							Total number of NEs
			Systematic	Abbreviation	Family	Formula	Identifier	Multiple	Trivial
Train	3500	30418	6656	4538	4090	4448	672	202	8832	29438
Development	3500	30445	6816	4521	4223	4137	639	188	8970	29494
Test	3000	8655	5666	4059	3622	3443	513	199	7808	25310