huh? They match your contribution dollar for dollar one time only when you make that contribution. Your contributions and the match go into your 401(k) account and you choose which funds to invest them in. The value of these funds can then increase (or decrease) earning you even more money.
The dollar for dollar ratio itself should be fairly stable. However, if the company runs into financial trouble, they may choose to save money by reducing the match to say, $0.50 for every $1 you contribute, or eliminate the match altogether.
Although the matching ratio varies from company to company, pharmacists are typically able to get around $6,000-$7,000 in employer matching contributions each year, so do not pass up this free money!