How many minority leaders have not been registered in Federal Election Commission data?
minority leaders is a title; have not been registered in Federal Election Commission data refers to fec_id IS NULL OR fec_id = ''
SELECT COUNT(*) FROM current AS T1 INNER JOIN `current-terms` AS T2 ON T1.bioguide_id = T2.bioguide WHERE T2.title = 'Minority Leader' AND (T1.fec_id IS NULL OR T1.fec_id = '')