295.00 ppm (1900)
319.02 ppm (May 1960)
356.32 ppm (May 1990)
390.18 ppm (May 2009)
392.95 ppm (May 2010)
394.29 ppm (May 2011)
396.87 ppm (May 2012)
399.89 ppm (May 2013)
401.88 ppm (May 2014)
|
403.70 ppm (May 2015)
407.70 ppm (May 2016)
409.25 ppm (May 2017)
411.31 ppm (May 2018
414.83 ppm (May 2019)
417.16 ppm (May 2020)
419.13 ppm (May 2021)
420.99 ppm (May 2022)
424.00 ppm (May 2023)
|