We've updated our reliability stats for the Volt to include owner experiences through March 31, 2013.
Repair frequencies, in terms of repair trips per 100 cars per year:
2013 Volt: 35, moderate, small sample size (which probably explains why it's higher than the 2012)
2012 Volt: 13, low
We have two additional statistics, "Nada-odds" and "Lemon-odds", to indicate the percentage of cars with no repairs in the past year and those that required 3+ trips to the repair shop:
2012 Volt: 88, < 1
We'll have further updates in August and in November. The more owners participate, the more comprehensive and precise these will be.
For the details, including the descriptions of reported repairs, and to sign up to help improve this information:
Chevrolet Volt reliability ratings and comparisons