Nobody really knows what the true effects of volcanic activity are hand how much they change the weather. Land based volcanoes emission of gasses and particulates are guessestimations. How much extra h2o is forced into the atmosphere from underwater volcanoes is barely discussed.
Currently there are around 31 erupting volcanoes, in 2013 there were 80 or so. I didn’t look to see what the volumes of expelled material were then or are now to make a comparison.