The two screenshots below were taken at the same time from the same webpage/website: https://www.co2.earth/.
When one goes back to get the link, the link for the upper graph is: https://www.co2.earth/earths-co2-main-page; the link for the lower graph is: https://www.co2.earth/keeling-curve-monthly. I assume these are dynamic links.
It should be noted that atmospheric CO2 in January 2015 was 402.53, and atmospheric CO2 in January 2016 was 402.52.
This is a most incredible science experiment. I hope they don't "change" the way this data is collected or presented over the next 100 years.