To see precise methane values, hover your mouse cursor over the blue graph trace. (However, all values are shown with about one more significant digit than is warranted by the precision of the measurements, and the ice core values are less accurate than the Mauna Loa measurements.)
For an examination of methane's atmospheric lifetime, radiative forcing, and warming effect, see:
1840-1992 data (in light blue) is from
(ice cores), interpolated.
1984-present data (in dark blue) is from https://www.esrl.noaa.gov/gmd/webdata/ccgg/trends/ch4/ch4_annmean_gl.txt (measurements at Mauna Loa
The figures are annual averages.
We also have a similar graph for carbon dioxide (CO2), and a combined graph with both CO2 and CH4.