The base year for economic indicators, such as GDP or inflation, typically changes every five to ten years, depending on the country and the specific indicator being measured. This change is made to reflect more current data and to improve the accuracy and relevance of economic analyses. However, the exact frequency can vary based on government policy, economic conditions, and the availability of updated data.
The base-year value is ordinarily shown as a percentage with the percentage symbol omitted, often 100.0. An example might be Base Year percentage 100.0 and Current Value 139.9.
You normally divide by the previous year. The general rule for calculating a relative (or percentage) change is to look at the change compared to the base, or earlier, year.
You should change them once a year. We have the same lights, just to be sure it doesn't hurt to change them every year.
once a year
Variable annuity insurance is insurance that has a variable year to year and it can change upon facts that change such as your base description of how you manage your life.
It depends on the year.
twice a year
once a year
result of a series of numbers related to the base number as in a percent change over years related to the base year
You protect derived classes from breaking when you change the internal parts of the base class by making sure that the public (or protected) parts of the base class do not change. Only the private parts may change. If the public interface changes, then the derived class must often change.
The prime rate normally changes only when the national banks decide to raise or lower their base rate. The prime rate has been known to not change for years but it has also been known to change several times in one year. http://en.wikipedia.org/wiki/Wall_Street_Journal_prime_rate
The FICA tax base, which includes Social Security and Medicare taxes, can change annually, typically in response to adjustments in the national average wage index. The Social Security portion of the FICA tax has a wage base limit that may increase each year, reflecting increases in average wages. However, the Medicare portion does not have a wage base limit and applies to all earned income. Changes are usually announced by the Social Security Administration in the fall before the new tax year begins.