Converting daily data to annual for a list of dataframes

I have a list of 50 data frames and each data frame contains daily data in the columns. For the single data frame, I used the following code:

Daily$Month<-floor_date(Daily$Date,"year")
Annual<- Daily %>%
group_by(Year) %>%
summarise_each(funs(mean))

How can I write and apply a function to convert the daily data to annual for all the data frames in the list?