All of the CO2 figures are annual averages.
We also have a similar graph for methane (CH4), and a combined graph with both CO2 and CH4.
Direct measurements of CO2 at Mauna Loa Observatory in Hawaii began in March, 1958. This is the annual average data graphed here (for 1959–2020):
ftp://aftp.cmdl.noaa.gov/products/trends/co2/co2_annmean_mlo.txt or
https://www.esrl.noaa.gov/gmd/webdata/ccgg/trends/co2/co2_annmean_mlo.txt
For monthly data see:
ftp://aftp.cmdl.noaa.gov/products/trends/co2/co2_mm_mlo.txt or
https://www.esrl.noaa.gov/gmd/webdata/ccgg/trends/co2/co2_mm_mlo.txt.
1850-1958 data is from http://data.giss.nasa.gov/modelforce/ghgases/Fig1A.ext.txt (ice cores).
1800-1850 CO2 data is from http://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/law/law_co2.txt (Law Dome ice cores, 75 year smoothed).