Derivation
variable: height (table[s]: arkk_arkq, arkl_arkq)
variable: heightf (table[s]: kduk_kduq, kdul_kduq, phdk_phdq, phdl_phdq)
variable: heights (table[s]: kduk_kduq, kdul_kduq, phdk_phdq, phdl_phdq)
variable: height_cm_hw (table[s]: NUTdata_KAR, NUTdata_LLW)
variable: height_final (table[s]: gap_combined)
<KDU & PHD data:>
egen height=rowmean(heightf heights)