Effectively rearrange large dataset

See attached: sample data in column A:C with output in E:G

in E2

=INDEX($B$1:$C$1,INT((ROWS($1:1)-1)/14)+1)

in F2

=MOD(ROWS($1:1)-1,14)+2004

in G2

=INDEX($B$2:$Z$15,MOD(ROWS($1:1)-1,14)+1,MATCH($E2,$B$1:$Z$1,0))