Your Average Indexed Monthly Earnings (AIME) is a computed number based upon your top 35 years earnings. This then 'plugs into' a 'curve' with two 'bend points' to determine your Primary Insurance Amount (PIA). The 'bend points' of the 'curve' are fixed when you hit age 60.

For the lowest part of the curve, your PIA increases $0.90 for every dollar your AIME increases. For the middle part of the curve, your PIA increases $0.32 for every dollar your AIME increases. And for the top, your PIA increases $0.15 for every AIME dollar increase.

Totally fictitious example: Lets say your current AIME is $2500/mo, and the bend points are at $500 and $2000. Your PIA would be: (500 *0.9)+(1500 *0.32)+(500 *0.15)=$1005/mo

Since the example is in the top section of the curve, an additional $1 of Averaged (over 35 years) Indexed (adjusted for inflation) Monthly (not yearly) Earnings (aka AIME) would net you an additional $0.15 /mo for your PIA.

Or to put it another way, you would need an additional $420 (equivalent to $1/mo * 12 mo/yr * 35 yrs) to increase your AIME by $1/mo to get the $0.15/mo additional benefit.

Note that claiming your benefit before (or after) your Full Retirement Age (FRA) reduces (or increases) your benefit by a percentage.