US vs China Cumulative Emissions - Parity?

The US has emitted more CO2 cumulatively than has China. The current ratio, for CO2e starting in 1850, is 1.69. When will it equal one?

Our World in Data gives this chart

but their table of data is not very accommodating, having everything, by country, by year, shoved into a single column.

So instead I'm going to use the much more reasonable data presentation from PIK (Potsdam Institute of Climate Research), which begins in 1850.

Then, the ratio of US CO2e to China CO2e emissions is, since 1850

This is all emissions, in CO2-equivalent units, for the Kyoto gases, which are 

Carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and the so-called F-gases(hydrofluorocarbons and perfluorocarbons) and sulphur hexafluoride (SF6). Each gas is weighted by its global warming potential and aggregated to give total greenhouse gas emissions in CO2 equivalents.

Up until about 1880, China actually led the US, presumably from methane emissions from growing rice.

Since just after the peak, say starting in 1970, this ratio is very linear and looks like

This linear trend reaches 1 in the year 2028.8--just 5.2 years from this August 1st.

Of course, China now has a population 4.2 times that of the US, so per-capita this ratio isn't even in the ballpark of one. 

And per-capita, not per-country, is really how carbon emissions should be accounted for. Americans are still a much bigger energy hog and carbon polluter than the Chinese, and this may never reach parity. Even more so when you consider that we've outsourced some of our manufacturing (=carbon emissions) to China. Perhaps that's the only reason why US annual emissions have been decreasing in recent years. I'm pretty sure someone somewhere has been keeping the data on this.