documentclass{article}
usepackage{pgfplots, pgfplotstable}
usepackage{filecontents}
usepackage{indentfirst}
usepackage{amsmath}
usepackage{float}
usepackage{hhline}
usepackage{booktabs}
usepackage[strict]{changepage}
usepackage[position=top]{subfig}

renewcommandthesection{}
makeatletter
renewcommandthesubsection{@arabicc@subsection}
makeatother

begin{filecontents}{data.dat}
28.1 0.7 0.9 1.2 1.4 1.5
40.0 11.2 11.7 12.0 12.2 12.9
44.7 18.2 19.3 19.7 19.8 20.4
50.9 28.0 28.9 29.4 29.6 30.1
57.0 43.2 42.2 41.6 40.7 40.4
61.5 50.2 51.0 52.1 52.6 52.7
67.0 62.8 64.5 65.5 65.6 68.5
72.2 78.3 79.2 80.7 80.8 82.7
end{filecontents}

pgfplotsset{compat=1.14}
pgfplotstableread{data.dat}Data

begin{document}
newcountcountuno
newcountcountdos

begin{table}[H]
begin{tabular}{lll}
toprule
$D$ & $h$ & $h/D$\
midrule
gdeftablecontents{}%
foreachrow in {0,...,34}
{%
        countdos = row
        countuno = row
        dividecountuno by 5
        dividecountdos by 5
        multiplycountuno by -5
        advancecountuno by row
        pgfplotstablegetelem{countdos}{0}ofDatapgfmathsetmacroelemtable{pgfplotsretval}%
        ifnumcountuno=1
                xdeftablecontents{%
                        unexpandedexpandafter{tablecontents}%
                        noexpandpgfmathprintnumber{elemtable}%
                }%
        fi
        pgfplotstablegetelem{countdos}{countuno}ofDatapgfmathsetmacroelemtabledos{pgfplotsretval}%
        pgfmathsetmacroelemtabletres{elemtabledos / elemtable}
        xdeftablecontents{%
                unexpandedexpandafter{tablecontents}%
                & noexpandpgfmathprintnumber{elemtabledos} & noexpandpgfmathprintnumber{elemtabletres}noexpand\
        }%
        ifnumcountuno=5 xdeftablecontents{%
                        unexpandedexpandafter{tablecontents}%
                        noexpandmidrulenoexpand\
                }%
        fi
}
tablecontents
bottomrule
end{tabular}
end{table}

end{document}