Figure that in almost any time based situation, people round off. For example, if the time frame is in months, the two weeks won't matter. If the time frame is in years, the months won't matter (1.5 years may be discrete, but 2 years/8 months becomes "almost 3 years").
More relevant is likely the nature of your position. In jobs where the process for doing the work is extremely clear, the turn around time on any given task is fast, or the job is largely interchangeable from company to company - the learning curve is a very small factor. For knowledge working jobs - where typically each company has a unique process, team bonding is important, company culture is relevant and it requires some degree of business domain knowledge to complete the job - then it is expected that a learning curve can be anywhere from 3 months to a year. As a result, companies typically invest in a semi-productive employee's inefficiency and training needs (it can slow the entire team down) for up to a year before expecting that the new employee is 100% as useful as the pre-existing employees.
So... the larger question is - what kind of job is yours? I know plenty of folks, for example, who work in kitchens or retail, where many jobs in a year is no big deal. They quit if a shop closer to home opens up, if they get moved across shifts or anything else.
In the computer industry, quitting in a year isn't such a great option, and it isn't a big difference whether you quit in 10 month or 1 year. If I am interviewing someone and they leave in a year or less, they better have a great story on why. Typical cases of good "whys" include promotions, going to school for a career boost/change, radical career shifts, demise of the company, downsizing of the group, or family/health calamity. What the interviewer has to decide is "will this guy stick around with us long enough to pay us back for his inefficiency".
The length of time of an average term of service in a given field can be wildly variable. You probably want to hunt around in your particular field and location and see if there's a norm. My suspision is, in most knowledge working domains, 10 months vs. 1 year won't matter - the key will be why you left.