Once the audience understand what they are seeing, they will be more receptive to your explanation of it, for example 'As you can see from this slide, investment appears to be increasing more slowly than before'. It is important not to cram too much into your slides, otherwise it becomes confusing. Too few points are always better than too many. And you could vary the number to add interest. Occasionally putting only one point on a slide will change the pace of the presentation and help to keep the audience alert.
Text is the most widely used form of visual aid.
It is usual to set out key ideas as bullet points. But keep the bullet points simple. Whatever you do, be sure to leave lots of space so your points are easy to read. Graphs are useful for showing how variables change over time, or for showing how one variable relates to another. Beware of including more than three variables on one graph as they may confuse.