Very interesting page of Mormon statistics. I think it’s clear from these charts that Mormon growth is on a downward trajectory and they have never been as big as JWs. In particular the baptism figures are striking, plus the chart of active members as opposed to nominal members.
Despite being much more proactive in baptising members of the public, Mormons only managed to baptise 233,000 last year. They only have 30,000 congregations worldwide, compared with around 120,000 JW congregations, and there are only around 5 million active Mormons compared with over 8 million JW publishers.