A lot less than usual. Am on about 780 miles so far this year, whereas normally by mid May I would be on about 2000. I have, on the other hand, rowed almost 500,000 metres on my indoor rower, whereas normally by mid May I would have rowed 50,000. So cycling is at 35% of normal and rowing is at 1000% of normal. No doubt the statistically challenged would now claim that I have been doing much more exercise under lockdown than normal.
I have, however, with reference to not travelling too far from home, carrying on social distancing, but being allowed to exercise as much as you like (if that was what Sunday did actually say?), used Ride with GPS to prove that I can ride 300km in a continuous loop without intersections or crossings around the borough of Basingstoke and Deane staying pretty much on rural roads. Another of those great ideas that will probably never be ridden but was fun composing.