the MET to be applied to any given year, that year must first be considered a grace year, which requires that it either be the first year in which the beneficiary is entitled to benefits under Title II of the Social Security Act, during a year in which there was at least one month in which the beneficiary was not entitled to Title II benefits, or a year in which the beneficiaries entitlement to Title II benefits was terminated for reasons other than death. The grace year must also include at least one non-service month, which is any month in which the beneficiary neither earns wages over the monthly exempt amount nor performs substantial services in self-employment. Services are considered substantial in self-employment if they consist of over 45 hours in a single month or 15 hours if it is a "highly skilled occupation." The monthly exempt amount is 1/12 of the yearly exempt amount for that year. For first tier beneficiaries, the monthly exempt amount is $1,130 and $3,010 for second tier beneficiaries for 2008. The MET is helpful for beneficiaries who retire in the middle of the year and who would be penalized for earlier earnings under the AET. Windfall elimination provision (WEP) The Social Security Amendments of 1983 (Public Law 98-21) created the WEP. Beneficiaries who have been employed in work that does not pay into the Social Security Trust Fund and who receive a pension from that employment based upon earnings which were not covered by Social Security may see their benefits partially offset by the WEP. The WEP applies once the beneficiary is both entitled to RIB and is entitled to the pension or meets all the requirements except for stopping work or filing an application. There is a possibility that with enough years of coverage (YOC) that the WEP may be either reduced or waived. Anyone with 30 or more YOCs is exempt from the WEP. Beneficiaries with between 21 and 29 YOCs will have the effect of the WEP reduced. The WEP may reduce the benefit in various ways, taking various rules and computation methods into account (see main article). The WEP was developed as the result of the progressive method in which the PIA is computed. Since those with less earnings on the record receive a comparatively larger percentage of their average income, under normal computations a beneficiary who paid in little