Is estimatedly a word?

Is ‘estimatedly’ a word? My spell checker highlights it and Google returns only 35k results so I guess it is not, though I cannot "see" what is wrong with it.

I am using it in this context:

According to McKinsey’s 2016 report, `United States alone has more than two zettabytes (2,000 exabytes) of data’ estimatedly, […]