Shouldn't taxon be unique within an ecocode system? This query run on 2017, 2018 and 2019 imports gives different counts for total number of ecocodes and distinct taxon_id.
SELECT count(*), count(distinct e.taxon_id)
FROM tbl_ecocodes e
JOIN tbl_ecocode_definitions ed USING (ecocode_definition_id)
JOIN tbl_ecocode_groups eg USING (ecocode_group_id)
WHERE ecocode_system_id = 2;
Shouldn't taxon be unique within an ecocode system? This query run on 2017, 2018 and 2019 imports gives different counts for total number of ecocodes and distinct taxon_id.