Historical clue formulations

• I.R.S. employee: Abbr. — 2015-05-22
• C.P.A., at times: Abbr. — 2012-11-29
• I.R.S. worker: Abbr. — 2005-11-27
• I.R.S. exam: Abbr. — 2005-11-15
• I.R.S. agent: Abbr. — 2004-01-11
• I.R.S. employee: Abbr. — 2001-05-12
• Sch. meeting room — 1999-01-31