Estimating percentile ranking for number not in distribution

Hi,

I have a data set of simulated treatment estimates and I want to see where another treatment estimate not in the data set falls in this distribution. I tried to use pctile to estimate the percentile of the additional treatment effect, but it seems like the only way to do this is to add the new value into the distribution of treatment effects. Is there a way to estimate its percentile rank without adding it to the distribution? My goal is to just have the new treatment effect called in as a local, if possible.

Thanks!