In this graph, a week is indicated by the starting day of that week. For instance, at the moment of writing, the current week (week 46) is indicated by the starting day of the week: Monday November 15th.

From this graph a number of observations can be made:

1. Up until June of 2021 the weekly active users on Uniswap had been much greater than the weekly active users on Sushiswap. Starting from July 2021 the number of weekly active users has been similar.
2. The number of weekly active users on Sushiswap on Ethereum has been relatively stable over the past year.

The first observation can be explained by the fact that Uniswap is still the largest DEX in terms of users and volume. Therefore, during the Jan-May crypto run of 2021, Uniswap saw the largest increase in users as new users were turning to the largest DEX.

The second observation can be explained by the number of blockchains Uniswap and Sushiswap are available on. While Uniswap is available on three blockchains, Sushiswap is available on over a dozen blockchains. Since the graph only shows the active users on the Ethereum blockchain, it is reasonable that the number of active users on Sushiswap has been relatively stable, since most of Sushiswaps users are on other blockchains.