What is the best way to generate a timechart count and overlay a trendline of expected goal growth?

Hi, I want to generate a timechart count of actual values and overlay a trendline of expected goal growth. Basically I want to trend how my data is growing over time with a visual of how I hoped it grew over time. index=myDownloads | timechart span=1w count as Downloads Above, is an example of the base query, and I tried appending static data using a lookup table with prepopulated weekly download numbers to no avail. Before I go too far down this road, is there a way easier way I can plot a simple slope of static values growing 1% each week? Thank you!