Fully shielded transactions

SELECT alltxs.block_timestamp_month, fulltxs.fully_shielded_count, 100*fulltxs.fully_shielded_count/alltxs.count AS fully_shielded_percent FROM
  (SELECT
    block_timestamp_month, count(distinct `hash`) AS fully_shielded_count
    FROM
      `bigquery-public-data.crypto_zcash.transactions` AS zec_txs
    WHERE
      NOT EXISTS (SELECT 1 FROM UNNEST(zec_txs.inputs) WHERE NOT type = 'shielded')
      AND NOT EXISTS (SELECT 1 FROM UNNEST(zec_txs.outputs) WHERE NOT type = 'shielded')
    GROUP BY block_timestamp_month) fulltxs
INNER JOIN
  (SELECT
    block_timestamp_month, count(distinct `hash`) AS count
    FROM
      `bigquery-public-data.crypto_zcash.transactions` AS zec_txs
    GROUP BY block_timestamp_month) alltxs
ON fulltxs.block_timestamp_month = alltxs.block_timestamp_month
ORDER BY alltxs.block_timestamp_month