what was the three most commonly carried out specimen tests until 2104?
select t1.spec_type_desc from ( select microbiologyevents.spec_type_desc, dense_rank() over ( order by count(*) desc ) as c1 from microbiologyevents where strftime('%y',microbiologyevents.charttime) <= '2104' group by microbiologyevents.spec_type_desc ) as t1 where t1.c1 <= 3