In the comments you said that the number of customers is constant, say $N$.
So every day $N$ people can participate and in a whole week $7N$ people can participate.
The percentages give you the absolute number of people participating at a given day by multiplying it with $N$.
For example on day 1 100% of customers participate, meaning there are $1\cdot N$ customers.
On day 2 50% of customers participate, thus there are $0.5\cdot N$ customers.
Now to calculate the percentage of a whole week you just add the number of participants at each day of the week and divide by the total number of people that could have participated (and then multiply by 100 to get the percentage).
So if $p_d$ is the percentage of people participating at day $d$, then the percentage $P_{\text{week}_1}$ of people participating in the first week will be:
\begin{align} P_{\text{week}_1}&=\left(\frac{\sum_{d=1}^{7} \frac{p_d}{100}\cdot N}{7N}\right)\cdot 100\quad\%\\
&=\sum_{d=1}^{7} \frac{p_d}{7} \quad\% \end{align}
For the next week you start the sum at $d=8$ and sum up to $d=14$ etc.
Getting the percentages for the months is an analogous process.
Does this answer your question?