Since I found the data figured I'd post it. Pretty much the same comments as the taxation figures. Government expenditure is even messier than tax expenditure, I guess I'm used to seeing smoothed charts. Unfortunately the data set isn't as good, several states start late in the series, though oddly enough Korea starts earlier. In any case, there's a sharp spike for the current recession but the same kind of flattening of spending occurs as with taxation, though it's a little harder to see and looks less clustered. Korea is the only country with a clearly rising government expenditure, but that's expected. Sweden breaks 70% spending and Finland breaks 60%, though neither of them maintains it for long. I assume this is due to a recession and counter cyclical spending, but am too lazy to do the research to check for temporary blips. On this chart we get a few countries whose spending settled above 50% (though Sweden's data series is so short and noisy I can't say they look like they've settled into anything), Belgium, France, Austria, Denmark, Sweden, and Finland (France's curve looks like it still may have a slight upward slope, probably because they have completely unsustainable labor practices, and Belgium just barely makes the cut).
For the most part though, spending seems to become basically flat between 40 and 50% of GDP in most cases, and this has been stable for some time. Unfortunately this data set only begins in 1970 so it leaves out the years that experience rapid growth of government. If the curve had been there it would be more obvious how much leveling out there is post 1980 (and from the chart a leveling out that proceeded somewhat messily between 1980 and 1990) for many countries compared to the rapid rise of the state in the 50s and 60s, though the tail end of this is visible in the 70s for the few countries the data is present for (I especially regret not having Spain which started so much less developed and caught up). Korea appears to be the only state that remains on a clear upward trajectory, while all countries show a recent spike this is to be expected due to the shrinking of the economy in the recession, and judging from the sharp spikes and recoveries common before there is no reason to think this will be sustained.
[Unfortunately I haven't found a good way to put graphics of this size into the blog yet. I may eventually find a way for now it should be enlargeable in your browser or you can get the OECD data directly. It's much clearer in Openoffice where I can highlight individual lines.]