getting a divorce what percentage of my husband's pensions will i get retired after 20 years i was married to him17 of those years

Yes you are entitled to a percentage.  However, to determine the exact amount, there are actuary charts that will determine your percentage.  There are factors that are taken into account inculding your age and the age of your spouse.  Some attorneys determine the amount themselves but many attorneys send these out to a qualified accountant or actuary who can comprehensively determine the precise amount that is due and owing.  Most likely there is an additional fee for the accountant or actuary.