Ah sorry, I meant if you select the American and British corpora separately.
You can put them on one chart with
is very concerning:eng_gb_2012,is very concerning:eng_us_2012,is very worrying:eng_gb_2012,is very worrying:eng_us_2012
#7 I must have missed the other thread.
What I also find interesting is that "is very worrrying" seems to be more common in BE and that the Brits seemed to stop worrying around 1975, which seems odd considering what I remember of the political situation in the seventies (financial crisis, oil crisis, three-day week, Harold Wilson . . .)