My outlets that have been working fine in my new house for 12 years suddenly went dead. I checked the breaker and it was not tripped. I measured the voltage and found 100 VAC from neutral to hot. I then measured Neutral to ground and found 20 VAC and 120 VAC from Hot to ground. Some how I am getting 20 volts on the neutral which explains why I'm only measuring 100 volts between neutral and hot. I change a GFI with no help. One last thing is the 2 outlets closest to the circuit breaker measure a perfect 120 vac where the circuits further down the line have the neutral 20vac. Also three of the 7 outlets are outside recepticals but appear OK on the surface.
How is this possible and what could the issue be?

Poor neutral connection somewhere. If outlets were wired using the "Quick Connect" holes in the back of the outlet, rewire using the screw terminals.