# Logarithmic axis with more ticks

I have a problem with y-axis of my graph produced with this code:

\documentclass{book}
\usepackage{tikz}
\usetikzlibrary{datavisualization}
\begin{document}

\begin{figure}[htbp]
\centering
\begin{tikzpicture}
\datavisualization [
scientific axes=clean,
x axis={length=0.8\textwidth, ticks=some, label={Generation}},
y axis={length=0.56\textwidth, logarithmic, ticks={minor steps between steps}, grid, label={Costs}},
visualize as line/.list={best,average},
legend=north east inside,
best   ={label in legend={text=best cost}},
average={label in legend={text=average cost}},
style sheet=vary dashing
]
;
\end{tikzpicture}
\caption{GA: graphical representation of costs improvement shown for the average and the best VA.}
\label{fig:GAimprovement:eb_555AICH}
\end{figure}
\end{document}


The files with data: average.csv and best.csv

What I would like is for labels to also appear at the minor ticks (i.e. 8*10^6, 9*10^6 and 1,1*10^7). I read in the documentation that the minor ticks do not have labels, but is there a workaround? I already tried ticks={at={8000000,9000000,11000000}} to brute force the ticks, but to no avail ...

What is needed is ticks and grid={major at={8000000.0,9000000.0,10000000.0,20000000.0}} to get the desired effect.