Getting a pension bigger than your old paycheck is still rare in government, but it is happening to more and more retirees each year.

The second inflation-related, federal pension raise of the year, to be announced Thursday, may pusch thousands of senior civil servants and military officers into retirement for financial reasons.

Dur to the strange combination of frozen or "depressed" federal pay raises and twice-a-year pension adjustments based on inflation, a growing number of federal retirees now get bigger government checks than their former paychecks.

Annuities for nearly 3 million federal-military retirees, including 100,000 here, are tied to living costs as measured by the Consumer Price Index. Retirees received a 3.9 percent inflation catch-up in March, and are due another in September.

The CPI figure to be released Thursday will represent June living costs. June is the final month in the current countdown. It will determine how much retirees get this fall.

Retirees are already guaranteed a minimum 5.6 percent raise, based on the May CPI. But the June figure is certain to be higher, and that will mean a bigger annuity increase. Although President Carter has slapped a 5.5 percent limit on federal-military pay, many high-ranking aides will not even get that. The increases will probably be denied anybody making $47,500 or more.

Because of scaled-down raises, or no increases at all, many high-level bureaucrats and military types are expected to retire to get pensions that are adjusted to the escalating cost-of-living.

Each CIP adjustment is major news since it also affects Social Security and some VA payments, wages and pensions in some private firms and even alimony and child support in some cases.

Federal-military pension changes are based on the CPI data under the "Revised Index for Urban Wage Earners and Clerical Workers." There is an easy way to figure out what the CPI means, in terms of percentage raises, if you have the correct table.

This table shows possible CPI readings and translates them into percentage pay raises for retirees. It starts with 214.3 since that was the CPI level for May. You can use this table to determine the amount of the coming pension increase:(TABLE) CPI(COLUMN)Annuity Revised Index(COLUMN)Increase 214.3(COLUMN)5.6 percent 214.4 or 214.5(COLUMN)5.7 percent 214.6 or 214.7(COLUMN)5.8 percent 214.8 or 214.9(COLUMN)5.9 percent 215.0 or 215.1(COLUMN)6.0 percent 215.2 or 215.3(COLUMN)6.1 percent 215.4 or 215.5(COLUMN)6.2 percent 215.6 or 215.7(COLUMN)6.3 percent 215.8 or 215.9(COLUMN)6.4 percent 216.0 or 216.1(COLUMN)6.5 percent(END TABLE)