latest data ppb (parts per billion)and Growth rate:
https://gml.noaa.gov/ccgg/trends_ch4/

Methane is reported as a “dry air mole fraction”, defined as the number of molecules of methane divided by the total number of molecules in the sample, after water vapor has been removed. The mole fraction is expressed as nmol mol-1, abbreviated “ppb” (for parts per billion; 1 ppb indicates that one out of every billion molecules in an air sample is CH4).

The annual increase in atmospheric CH4 in a given year is the increase in its abundance (mole fraction) from January 1 in that year to January 1 of the next year, after the seasonal cycle has been removed (as shown by the black lines in the figure above). It represents the sum of all CH4 added to, and removed from, the atmosphere during the year by human activities and natural processes.

Our first preliminary estimate for the annual increase of a particular year is produced during April of the following year, using available data from the previous year. It is important to recognize that the initial, April estimate of the annual increase is likely to change significantly as more data are added to the analysis. That estimate will be updated in subsequent months as more samples are measured for CH4 and included in the analysis.
By autumn of the following year the annual increase will typically converge toward a “final” value.