Interpretation of Dynare results

Can somebody help me with the interpretation of Dynare results?
I include GDP at levels (yf) starting from 1970, and have the growth rate of yf and detrended (diff(log (yf)) in yf_obs.
yf_obs = detrend(diff(log(yf)), ‘constant’);

yf is formal sector GDP
ys is shadow sector GDP
total GDP y = yf+ys

In the model, I have defined y as follows;

yf=exp(zf)*kf(-1)^ALPH*nf^(1-ALPH);                     % (1)
ys=exp(zs)*ks(-1)^ALPH_S*ns^(1-ALPH_S);         % (4)
y=yf+ys;                                                                  % (12)
ysy=ys/y;

I get the smoothed variables in oo_.smoothedvariables as the output.

            ys/y
            
1971	0.309518199
1972	0.258122016
1973	0.330331209
1974	0.319470245
1975	0.402108905

My problem is, do these values show the percentage deviation from the steady state? I want to get the size of the Shadow Economy as a share of total GDP timeseries.

That part of the estimation is irrelevant for your question as it just clarifies how the model parameters were estimated. Based on your variable definitions, everything is in levels, and you defined ysy as the ratio of levels. Thus, what you are seeing for the smoothed variables is the level share of ys in y, which is roughly 30 percent on average.

@jpfeifer Thanks a lot for the clarification!!!