Whenever any insurance company doing business in this state shall make it appear to the Commissioner, by evidence satisfactory to him, that one-fourth of its total assets, as of December 31 of any taxable year, exclusive of direct obligations of the United States, consists of or is invested in any or all of the following classes of property:

(1) General obligation bonds of this state or of any political subdivision of the State of Georgia;

(2) Revenue bonds or revenue anticipation certificates of any county, municipality, or political subdivision of this state;

(3) Revenue bonds or revenue anticipation certificates of any authority or public corporation created by or pursuant to the laws of this state;

(4) Real estate situated in and subject to taxation by this state or its political subdivisions;

(5) Tangible personal property located in this state and subject to taxation by this state or its political subdivisions;

(6) Loans secured by liens on real estate situated in this state;

(7) Policy loans on insurance policies issued by the company on lives of persons resident in this state;

(8) Intangible property having a taxable situs in this state; or

(9) Shares in Georgia corporations in which the insurance companies are authorized to invest under the laws of this state,

then the gross premium tax levied by Code Section 33-8-4 shall be abated or reduced to 1 1/4 percent upon the gross premium of any company subject to taxation by said Code section and, if the amount so invested by any company shall be as much as three-fourths of its total assets, exclusive of direct obligations of the United States, then the said premium tax shall be abated or reduced to one-half of 1 percent upon the gross premiums of the company subject to taxation by said Code section.