And that work is somewhat more predictable in the short term, based on work orders that we’ve signed, but it will fluctuate based on the number of programs that we’re working on and the type of programs that our partners have asked us to work on. In recent history, that number has been averaging about $3 million per quarter. But what I really want to sort of get into is the milestone revenue here. And so we kind of fast forward or take a deeper dive on just the milestone and license revenue that is where we’re sort of seeing the lumpiness, if you will. And over the last 11 quarters, you’ve seen the milestone revenue range anywhere from $1 million a quarter all the way up to $31 million per quarter. So as you look ahead and think about what this revenue could look like going forward, I think it’s helpful to take a step back and look at where these numbers have been historically.
And the first thing to understand is that these TECVAYLI milestones that are shown here in this orange hashed line, are unusual in both their size and frequency. It’s not to say that we wouldn’t get milestones like this in the future. We have a number of Janssen programs that are in our clinical pipeline that have the exact same structure, right? So those could happen again. But this economic structure is a bit rare in our portfolio. And so I think you need to view these payments as more onetime in nature. So if I exclude TECVAYLI from the calculation and draw a regression line on the remaining milestone revenue, you get this blue line. It starts at $3.2 million and has an upward slope that grows up to about $3.6 million here in this current period.
If you were to include the TECVAYLI technology milestones in this regression line, you’re going to get a much, much steeper line and it wouldn’t be consistent with the base level of our business. So as you think about our license and milestone revenue going forward, I think it would be more appropriate to base your estimates on something that excludes these TECVAYLI milestones. So I also wanted to show you some metrics for our total active programs. But before I do that, I think it would be helpful to understand a breakdown of our active programs by license type. The first thing I want to say the most important thing is that 98% of our programs have downstream economics. There are only five programs out of the 314 programs that are active programs that have what I’m calling either a grandfathered or a prepaid license, right?
So only five, and all five of those are in clinical development. So they’re highly visible programs. But just to be clear, those are the only five. The other one that I think is worth mentioning just kind of calling out is the slice of the pie that’s shown here in green, which is the revenue share licenses. These are mostly from our academic institutions where there’s usually not an intent for that academic institution to take that molecule all the way to commercialization. And so the way these agreements work is that we will receive a portion or a revenue share of whatever that institution that discovers that molecule gets when they do a sublicense and license it out to someone. So while our percentage of that revenue share is defined upfront in our agreement with them, in many cases, we don’t know what the final economics will be until they do a license with someone else and then we’ll be able to understand what our share will be.
So what I’m going to show you in the next couple of slides are the metrics for the vast majority of our portfolio, which is the standard license shown here in purple, and I also have another slide for the ion channels. So if I take a look at that purple section of that pie chart, and we’re talking about 294 of our programs. And we exclude — so this does not include those grandfathered license. It doesn’t include the ion channels. And I’ve excluded the revenue share agreements where the economics are not yet known. So that’s the 294 programs that we’re talking about. And we add up all of the remaining milestones for those programs. That number is greater than $3 billion. Now obviously, we don’t expect every single one of those programs to be successful.
But I think you’ll agree there’s a significant opportunity available to us here. In addition, if you take a look in those 294 programs and take a look at what is the average royalty rate for all of those programs, it ends up being 3.2%. So if we look at the ion channel programs, the economics are even higher on a per program basis. So as Doug mentioned, we have programs ongoing with GSK and Roche. And the remaining milestones on those programs are approximately $1 billion. Now due to the confidentiality of those agreements, I can’t give you sort of the same number that I did for the other programs on royalties. But I can tell you that there are — they are tiered royalties that are higher than the standard antibody platform license that we have.
