By the way I calculated the integral of the spectral irradiance between the frequencies
180.5 and 1797.62nm, also as a plausibility check for myself, it is:
$$626.7597371000005 W/m^2$$
which sounds plausible since direct sun is about 1050 W/m2. I currently have to leave out the too small values (I.e. the fringes of the spectrum), since in the file the irradiances for these are written in exponentials and I would need to program a parser for that.

But this indicates that the rise in irradiation as mentioned above on the NASA page is eventually a bit outdated.
That is I caluclated a difference of 0.6 for the 180.5 and 1797.62nm range, which refers rather to 0.1% in 13 years and not in 24 years, but as already said fluctuations do play a role here.
Moreover for this special infrared range from 638.23nm to 981.15nm I get
$$ 192.13849465000004W/m^2$$
which is in 13 ys a rise of 0.5% where most of it happened in the last 2-3 years and not 0.1% in 24 ys. How good are the theories about the lifetime of the sun?