This chart tracks the proportion of transactions on the Bitcoin network which use use SegWit (BIP141).
I`ve also overlayed daily payment counts and the average fee charged per payment. Payments and transactions on the Bitcoin Network are not the same thing; each transaction processed by the network may contain many payment outputs to multiple third parties. (Payment count inside a single transaction is estimated by counting the total outputs and subtracting one, with the assumption that it is the unspent change).