api: Query Kusama's erasTotalStake and totalIssuance since genesis block until today

Hey there,

my aim is to query the full historic data of api.query.balances.totalIssuance and api.query.staking.erasTotalStake at every day in time for the Kusama network. So the end result should be to have the daily total staking rate since the genesis block.

At the moment I am running an archive node. The problem at the moment is, that I can not query the era of the genesis block. Code Example which should be something like that. Could you help me out?

const { ApiPromise } = require('@polkadot/api');

async function main () {
  const api = await ApiPromise.create();

  let blockNumber = 0;
  while (true) {
    const blockHash = await api.rpc.chain.getBlockHash(blockNumber);
    const activeEra = await api.query.staking.activeEra.at(blockHash);  
    if (activeEra.isSome) {
      const era = activeEra.unwrap().index;

      const totalCoins = await api.query.balances.totalIssuance.at(blockHash);
      const stakedCoins = await api.query.staking.erasTotalStake.at(blockHash, era);
      console.log('%s block number, %s staked coins and %s total coins for block hash %s', blockNumber, stakedCoins.toHuman(), totalCoins.toHuman(), blockHash);
    }
    blockNumber++;
  }
}

main().catch(console.error).finally(() => process.exit());