The percentage of entrepreneurs who who are worried about their ability to save for retirement is down sharply, new research reveals.

American Express OPEN Small Business Monitor released this finding in the first of two semiannual (spring and fall) reports that are based on a nationally representative sample of 813 small business owners/managers of companies with fewer than 100 employees. The survey was conducted via telephone by Echo Research between February and March.

The survey finds that the percentage of entrepreneurs who who are worried about their ability to save for retirement dipped to 70% from 81% last spring. One in five estimate they will need less than $750,000 (20%) to retire. An additional 29% say they will need between $750,000 and $1 million to retire and 21% say they will need between $1 million and $2 million.

Seventeen percent say they will need more than $2 million to retire.  On average, the survey says, the business owners believe they will need $1.24 million to retire, up slightly from the $1.205 million they reported in the spring of 2011

The report adds that optimism among small business owners is on the rise. More than half (56%, up from 48% last fall) have a positive outlook on business prospects over the next six months.

The survey notes the employment picture is also improving: 35% of small business owners plan to hire full- or part-time employees (up from 31% in the fall); and fewer said they will freeze hiring or cut back (44%, down from 61% in the fall).

The top priority of small business owners is maintaining their current business and sources of revenue (31%), followed closely by growing their business (29%, down from 37% last spring).

Based on how their businesses are performing, the survey adds, more than one-third of respondents (35%) believe the economy is recovering. Additionally, two-thirds (67%) say their workforce productivity has improved. And fewer are concerned about having cash available to pay bills (50% versus 59% last spring).