You are going to want to provide a range of high-quality evidence to support your persuasive presentation. Data and statistics can provide very useful, concrete information to contextualize a problem over time, make comparisons, pin point a significant event that influenced change in the data, and more.
This is not a comprehensive list of all the places you can look to for data or statistics related to your topic. For more options, consider which government agency would most likely collect information about your topic, and visit their official website.
There are tons of agencies and organizations that gather and make data freely available. When you are searching for data via a Google search, make sure to investigate what the organization or agency does to make sure you can trust the data they provide. Take a look at their "About" or "Mission" page to learn more about them, especially if you have not heard of an organization. Another thing you can use to help you determine the credibility of the source is the kind of website domain they use:
Typically, you trust that a .gov website is providing authoritative information about a topic. .edu and .org are more likely to provide credible information than a .com (which is for a commercial website), but you still will need to dig a bit deeper to determine what the organization does, what their mission is, how they collect their data, and more.