Try this
It is an array formula, so Ctrl-Shift-Enter=AVERAGE(INDEX(A1:T1,1,IFERROR(LARGE(IF(A1:T1<>"-",COLUMN(A1:T1),MIN(IF(A1:T1="-",99999,COLUMN(A1:T1)))),10),1)):T1)
Try this
It is an array formula, so Ctrl-Shift-Enter=AVERAGE(INDEX(A1:T1,1,IFERROR(LARGE(IF(A1:T1<>"-",COLUMN(A1:T1),MIN(IF(A1:T1="-",99999,COLUMN(A1:T1)))),10),1)):T1)
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Nihil simul inventum est et perfectum
Abusus non tollit usum
Last night I dreamed of a small consolation enjoyed only by the blind: Nobody knows the trouble I've not seen!
James Thurber